Preparing the fish: Remove the bones from the cod, cut into 6 x 6 cm pieces and pat dry in kitchen paper. Flour the cod pieces and arrange them in a single layer in a single layer in an oiled gratin dish.
Prepare the seasoning: Chop the onions and parsley. Preheat the oven to 130°C In a saucepan, brown the onions in the oil, add the garlic and anchovies and melt Add the garlic and anchovies and melt, crushing them with a fork. Remove from the heat, add the parsley, milk and Parmesan. Mix well. Season with salt if necessary. Cover the fish with the sauce.
Cooking time : Place the dish in the oven uncovered for 3 hours. If the top dries out, add milk and never stir. Serve with potatoes and a salad.
