Pepper the cod. (Frozen foods tend to already have a strong salt flavoring, so I don't use additional salt.) Coat with flour.
Melt the butter in the frying pan, and add the thinly-chopped garlic. Then add the cod and cook, being careful not to burn it.
Pour in the milk, reduce from medium to low heat, and simmer. The flour on the cod will dissolve into the milk, making the sauce creamy.
Check the flavor of the sauce (the creamy milk, white sauce) and if you find it to be thin, adjust with salt and pepper.
Transfer the cod to a serving plate and top with plenty of sauce. Garnish with minced parsley (or with green onions/scallions).
Story Behind this Recipe
I'm not a fan of the cod smell. But with this cooking method it's not an issue at all. The milk and garlic omits the raw fishy smell.
Once the cod has slightly browned, add the milk. When the milk comes to a boil, the cod has cooked through, and the milk is creamy, it's complete. Parsley has plenty of minerals such as β-carotene, vitamin C, vitamin E, and vitamin B.