Preheat oven to gas 6 / 200C / 400°F and pulse the bread into crumbs in a food processor. Spread the crumbs onto a shallow baking sheet and toast in the oven, stirring now and again, for 8 minutes. Transfer the crumbs into a shallow dish large enough to fit the fish fillets into

Combine the tartare sauce, half of the flour, the mustard, cayenne and parsley in another dish the same size. In a 3rd dish mix the remaining flour, salt & pepper and paprika

Raise the oven temp to gas 8 / 230C / 450°F and lightly grease a baking tray

Pat the fish fillets dry with kitchen towel.  Dredge the fillets one at a time lightly in the seasoned flour from dish 3. Dip the top and sides of the fillets in the tartar sauce / flour mixture from dish 2 (add a little rice milk if the mixture is too thick) then finally cover that coating with the bread crumbs, patting well all over to ensure they stick

https://cookpad.wasmer.app/us/recipes/336379-vickys-tartare-sauce-gluten-dairy-egg-soy-free

This breading is delicious on chicken too