diff --git a/conda-recipe/meta.yaml b/conda-recipe/meta.yaml
index 2a3adf3859..03cb440bca 100644
--- a/conda-recipe/meta.yaml
+++ b/conda-recipe/meta.yaml
@@ -39,7 +39,6 @@ requirements:
         - pineappl >=0.7.3
         - eko >=0.14.2
         - fiatlux
-        - frozendict  # needed for caching of data loading
         - sphinx >=5.0.2,<6 # documentation. Needs pinning temporarily due to markdown
         - recommonmark
         - sphinx_rtd_theme >0.5
diff --git a/pyproject.toml b/pyproject.toml
index 083545744f..970d3d5b1b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -67,7 +67,6 @@ pandas = "*"
 numpy = "*"
 validobj = "*"
 prompt_toolkit = "*"
-frozendict = "*"  # validphys: needed for caching of data loading
 # Reportengine needs to be installed from git
 reportengine = { git = "https://github.com/NNPDF/reportengine" }
 # Fit
diff --git a/validphys2/src/validphys/config.py b/validphys2/src/validphys/config.py
index c746995017..669e95553f 100644
--- a/validphys2/src/validphys/config.py
+++ b/validphys2/src/validphys/config.py
@@ -8,7 +8,6 @@
 import numbers
 import pathlib
 
-from frozendict import frozendict
 import pandas as pd
 
 from nnpdf_data import legacy_to_new_map
@@ -41,7 +40,15 @@
 from validphys.paramfits.config import ParamfitsConfig
 from validphys.plotoptions.core import get_info
 import validphys.scalevariations
-from validphys.utils import freeze_args
+from validphys.filters import (FilterDefaults, 
+                                AddedFilterRule,
+                                FilterRule,
+                                default_filter_settings_input, 
+                                Rule, 
+                                RuleProcessingError, 
+                                default_filter_rules_input
+                                )
+
 
 log = logging.getLogger(__name__)
 
@@ -1258,10 +1265,10 @@ def load_default_default_filter_rules(self, spec):
             )
 
     def parse_filter_rules(self, filter_rules: (list, type(None))):
-        """A list of filter rules. See https://docs.nnpdf.science/vp/filters.html
-        for details on the syntax"""
+        """A tuple of FilterRule objects. Rules are immutable after parsing.
+        See https://docs.nnpdf.science/vp/filters.html for details on the syntax"""
         log.warning("Overwriting filter rules")
-        return filter_rules
+        return tuple(FilterRule(**rule) for rule in filter_rules) if filter_rules else None
 
     def parse_default_filter_rules_recorded_spec_(self, spec):
         """This function is a hacky fix for parsing the recorded spec
@@ -1271,12 +1278,12 @@ def parse_default_filter_rules_recorded_spec_(self, spec):
         return spec
 
     def parse_added_filter_rules(self, rules: (list, type(None)) = None):
-        return rules
+        """
+        Returns a tuple of AddedFilterRule objects. Rules are immutable after parsing.
+        AddedFilterRule objects inherit from FilterRule objects.
+        """
+        return tuple(AddedFilterRule(**rule) for rule in rules) if rules else None
 
-    # Every parallel replica triggers a series of calls to this function,
-    # which should not happen since the rules are identical among replicas.
-    # E.g for NNPDF4.0 with 2 parallel replicas 693 calls, 3 parallel replicas 1001 calls...
-    @freeze_args
     @functools.lru_cache
     def produce_rules(
         self,
@@ -1286,10 +1293,9 @@ def produce_rules(
         default_filter_rules=None,
         filter_rules=None,
         default_filter_rules_recorded_spec_=None,
-        added_filter_rules: (list, type(None)) = None,
+        added_filter_rules: (tuple, type(None)) = None,
     ):
         """Produce filter rules based on the user defined input and defaults."""
-        from validphys.filters import Rule, RuleProcessingError, default_filter_rules_input
 
         theory_parameters = theoryid.get_description()
 
@@ -1317,8 +1323,7 @@ def produce_rules(
 
         if added_filter_rules:
             for i, rule in enumerate(added_filter_rules):
-                if not isinstance(rule, (dict, frozendict)):
-                    raise ConfigError(f"added rule {i} is not a dict")
+                
                 try:
                     rule_list.append(
                         Rule(
@@ -1331,7 +1336,7 @@ def produce_rules(
                 except RuleProcessingError as e:
                     raise ConfigError(f"Error processing added rule {i}: {e}") from e
 
-        return rule_list
+        return tuple(rule_list)
 
     @configparser.record_from_defaults
     def parse_default_filter_settings(self, spec: (str, type(None))):
@@ -1359,10 +1364,25 @@ def load_default_default_filter_settings(self, spec):
     def parse_filter_defaults(self, filter_defaults: (dict, type(None))):
         """A mapping containing the default kinematic limits to be used when
         filtering data (when using internal cuts).
-        Currently these limits are ``q2min`` and ``w2min``.
+        Currently these limits are ``q2min``, ``w2min``, and ``maxTau``.
+
+        Parameters
+        ----------
+        filter_defaults: dict, None
+            A mapping containing the default kinematic limits to be used when
+            filtering data (when using internal cuts).
+            Currently these limits are ``q2min``, ``w2min``, and ``maxTau``.
+        
+        Returns
+        -------
+        FilterDefaults
+            A hashable object containing the default kinematic limits to be used when
+            filtering data (when using internal cuts).
+            Currently these limits are ``q2min``, ``w2min``, and ``maxTau``.
         """
         log.warning("Overwriting filter defaults")
-        return filter_defaults
+        parsed_filter_defaults = FilterDefaults(**filter_defaults)
+        return parsed_filter_defaults
 
     def produce_defaults(
         self,
@@ -1370,34 +1390,40 @@ def produce_defaults(
         w2min=None,
         maxTau=None,
         default_filter_settings=None,
-        filter_defaults={},
+        filter_defaults=None,
         default_filter_settings_recorded_spec_=None,
     ):
         """Produce default values for filters taking into account the
         values of ``q2min``, ``w2min`` and ``maxTau`` defined at namespace
         level and those inside a ``filter_defaults`` mapping.
+
+        Within this function the hashable type FilterDefaults is turned into
+        a dictionary so as to allow for overwriting of the values of q2min, w2min and maxTau.
+        The dictionary is then turned back into a FilterDefaults object.
         """
-        from validphys.filters import default_filter_settings_input
+        if filter_defaults is None:
+            filter_defaults = {}
+        
+        if isinstance(filter_defaults, FilterDefaults):
+            filter_defaults = filter_defaults.to_dict()
 
         if q2min is not None and "q2min" in filter_defaults and q2min != filter_defaults["q2min"]:
             raise ConfigError("q2min defined multiple times with different values")
+        
         if w2min is not None and "w2min" in filter_defaults and w2min != filter_defaults["w2min"]:
             raise ConfigError("w2min defined multiple times with different values")
 
-        if (
-            maxTau is not None
-            and "maxTau" in filter_defaults
-            and maxTau != filter_defaults["maxTau"]
-        ):
+        if maxTau is not None and filter_defaults.get("maxTau", maxTau) != maxTau:
             raise ConfigError("maxTau defined multiple times with different values")
 
         if default_filter_settings_recorded_spec_ is not None:
-            filter_defaults = default_filter_settings_recorded_spec_[default_filter_settings]
+            filter_defaults = FilterDefaults(**default_filter_settings_recorded_spec_[default_filter_settings])
             # If we find recorded specs return immediately and don't read q2min and w2min
             # from runcard
             return filter_defaults
         elif not filter_defaults:
-            filter_defaults = default_filter_settings_input()
+            # if filter_defaults have not been set, load the defaults with default_filter_settings_input
+            filter_defaults = default_filter_settings_input().to_dict()
             defaults_loaded = True
         else:
             defaults_loaded = False
@@ -1413,7 +1439,9 @@ def produce_defaults(
         if maxTau is not None and defaults_loaded:
             log.warning("Using maxTau from runcard")
             filter_defaults["maxTau"] = maxTau
-
+        
+        # Turn the dictionary back into a hashable FilterDefaults object
+        filter_defaults = FilterDefaults(**filter_defaults)
         return filter_defaults
 
     def produce_data(self, data_input, *, group_name="data"):
diff --git a/validphys2/src/validphys/filters.py b/validphys2/src/validphys/filters.py
index cded762eab..e4b937c894 100644
--- a/validphys2/src/validphys/filters.py
+++ b/validphys2/src/validphys/filters.py
@@ -7,6 +7,8 @@
 from importlib.resources import read_text
 import logging
 import re
+import dataclasses
+from typing import Union
 
 import numpy as np
 
@@ -14,7 +16,7 @@
 from reportengine.compat import yaml
 import validphys.cuts
 from validphys.process_options import PROCESSES
-from validphys.utils import freeze_args, generate_path_filtered_data
+from validphys.utils import generate_path_filtered_data
 
 log = logging.getLogger(__name__)
 
@@ -99,18 +101,63 @@ class FatalRuleError(Exception):
     """Exception raised when a rule application failed at runtime."""
 
 
+@dataclasses.dataclass(frozen=True)
+class FilterDefaults:
+    """
+    Dataclass carrying default values for filters (cuts) taking into
+    account the values of ``q2min``, ``w2min`` and ``maxTau``.
+    """
+    q2min: float = None
+    w2min: float = None
+    maxTau: float = None
+
+    def to_dict(self):
+        return dataclasses.asdict(self)
+
+
+@dataclasses.dataclass(frozen=True)
+class FilterRule:
+    """
+    Dataclass which carries the filter rule information.
+    """
+    dataset: str = None
+    process_type: str = None
+    rule: str = None
+    reason: str = None
+    local_variables: Mapping[str, Union[str, float]] = None
+    PTO: str = None
+    FNS: str = None
+    IC: str = None
+
+    def to_dict(self):
+        rule_dict = dataclasses.asdict(self)
+        filtered_dict = {k: v for k, v in rule_dict.items() if v is not None}
+        return filtered_dict
+
+
+@dataclasses.dataclass(frozen=True)
+class AddedFilterRule(FilterRule):
+    """
+    Dataclass which carries extra filter rule that is added to the
+    default rule.
+    """
+    pass
+
+
 def default_filter_settings_input():
-    """Return a dictionary with the default hardcoded filter settings.
+    """Return a FilterDefaults dataclass with the default hardcoded filter settings.
     These are defined in ``defaults.yaml`` in the ``validphys.cuts`` module.
     """
-    return yaml.safe_load(read_text(validphys.cuts, "defaults.yaml"))
+    return FilterDefaults(**yaml.safe_load(read_text(validphys.cuts, "defaults.yaml")))
 
 
 def default_filter_rules_input():
-    """Return a dictionary with the input settings.
+    """
+    Return a tuple of FilterRule objects.
     These are defined in ``filters.yaml`` in the ``validphys.cuts`` module.
     """
-    return yaml.safe_load(read_text(validphys.cuts, "filters.yaml"))
+    list_rules = yaml.safe_load(read_text(validphys.cuts, "filters.yaml"))
+    return tuple(FilterRule(**rule) for rule in list_rules)
 
 
 def check_nonnegative(var: str):
@@ -457,10 +504,19 @@ class Rule:
 
     numpy_functions = {"sqrt": np.sqrt, "log": np.log, "fabs": np.fabs}
 
-    def __init__(self, initial_data: dict, *, defaults: dict, theory_parameters: dict, loader=None):
+    def __init__(self, initial_data: FilterRule, *, defaults: dict, theory_parameters: dict, loader=None):
         self.dataset = None
         self.process_type = None
         self._local_variables_code = {}
+        
+        # For compatibility with legacy code that passed a dictionary
+        if isinstance(initial_data, FilterRule):
+            initial_data = initial_data.to_dict()
+        elif isinstance(initial_data, Mapping):
+            initial_data = dict(initial_data)
+        else:
+            raise RuleProcessingError("Expecting initial_data to be an instance of a FilterRule dataclass.")
+
         for key in initial_data:
             setattr(self, key, initial_data[key])
 
@@ -511,7 +567,7 @@ def __init__(self, initial_data: dict, *, defaults: dict, theory_parameters: dic
         self.rule_string = self.rule
         self.defaults = defaults
         self.theory_params = theory_parameters
-        ns = {*self.numpy_functions, *self.defaults, *self.variables, "idat", "central_value"}
+        ns = {*self.numpy_functions, *self.defaults.to_dict().keys(), *self.variables, "idat", "central_value"}
         for k, v in self.local_variables.items():
             try:
                 self._local_variables_code[k] = lcode = compile(
@@ -592,7 +648,7 @@ def __call__(self, dataset, idat):
             return eval(
                 self.rule,
                 self.numpy_functions,
-                {**{"idat": idat, "central_value": central_value}, **self.defaults, **ns},
+                {**{"idat": idat, "central_value": central_value}, **self.defaults.to_dict(), **ns},
             )
         except Exception as e:  # pragma: no cover
             raise FatalRuleError(f"Error when applying rule {self.rule_string!r}: {e}") from e
@@ -628,7 +684,6 @@ def _make_point_namespace(self, dataset, idat) -> dict:
         return ns
 
 
-@freeze_args
 @functools.lru_cache
 def get_cuts_for_dataset(commondata, rules) -> list:
     """Function to generate a list containing the index
diff --git a/validphys2/src/validphys/loader.py b/validphys2/src/validphys/loader.py
index f4ec530108..88017eed68 100644
--- a/validphys2/src/validphys/loader.py
+++ b/validphys2/src/validphys/loader.py
@@ -675,10 +675,10 @@ def check_default_filter_rules(self, theoryid, defaults=None):
         th_params = theoryid.get_description()
         if defaults is None:
             defaults = default_filter_settings_input()
-        return [
+        return tuple(
             Rule(inp, defaults=defaults, theory_parameters=th_params, loader=self)
             for inp in default_filter_rules_input()
-        ]
+        )
 
     def _check_theory_old_or_new(self, theoryid, commondata, cfac):
         """Given a theory and a commondata and a theory load the right fktable
diff --git a/validphys2/src/validphys/tests/test_filter_rules.py b/validphys2/src/validphys/tests/test_filter_rules.py
index 05ee29827d..09055fa821 100644
--- a/validphys2/src/validphys/tests/test_filter_rules.py
+++ b/validphys2/src/validphys/tests/test_filter_rules.py
@@ -103,7 +103,7 @@ def test_good_rules():
     dsnames = ['ATLAS_1JET_8TEV_R06_PTY', 'NMC_NC_NOTFIXED_DW_EM-F2']
     for dsname in dsnames:
         ds = l.check_dataset(
-            dsname, cuts='internal', rules=rules, theoryid=THEORYID, variant="legacy"
+            dsname, cuts='internal', rules=tuple(rules), theoryid=THEORYID, variant="legacy"
         )
         assert ds.cuts.load() is not None
 
@@ -120,7 +120,7 @@ def test_added_rules():
             {
                 "speclabel": "fewer data",
                 "added_filter_rules": [
-                    {"dataset": "ATLAS_1JET_8TEV_R06_PTY", "rule": "pT < 1000", "reson": "pt cut"}
+                    {"dataset": "ATLAS_1JET_8TEV_R06_PTY", "rule": "pT < 1000", "reason": "pt cut"}
                 ],
             },
             {
diff --git a/validphys2/src/validphys/utils.py b/validphys2/src/validphys/utils.py
index 64e0e6d5de..1c77fd5b5d 100644
--- a/validphys2/src/validphys/utils.py
+++ b/validphys2/src/validphys/utils.py
@@ -1,42 +1,11 @@
 import contextlib
-import functools
 import pathlib
 import shutil
 import tempfile
-from typing import Any, Hashable, Mapping, Sequence
 
-from frozendict import frozendict
 import numpy as np
 
 
-def make_hashable(obj: Any):
-    # So that we don't infinitely recurse since frozenset and tuples
-    # are Sequences.
-    if isinstance(obj, Hashable):
-        return obj
-    elif isinstance(obj, Mapping):
-        return frozendict(obj)
-    elif isinstance(obj, Sequence):
-        return tuple([make_hashable(i) for i in obj])
-    else:
-        raise ValueError("Object is not hashable")
-
-
-def freeze_args(func):
-    """Transform mutable dictionary
-    Into immutable
-    Useful to be compatible with cache
-    """
-
-    @functools.wraps(func)
-    def wrapped(*args, **kwargs):
-        args = tuple([make_hashable(arg) for arg in args])
-        kwargs = {k: make_hashable(v) for k, v in kwargs.items()}
-        return func(*args, **kwargs)
-
-    return wrapped
-
-
 def generate_path_filtered_data(fit_path, setname):
     """Utility to ensure that both the loader and tools like setupfit utilize the same convention
     to generate the names of generated pseudodata"""