MACKEREL WITH TOMATOES

Cook the mackerel in the oven with the stock, sherry wine, herbs, lemon juice, and onion, cover with a buttered paper; when cooked, remove the skin, split the fish open, and remove the bones; butter a fireproof dish, lay in a layer of sliced tomatoes, a little salt and pepper, then a layer of fish and some tiny pieces of butter, repeat this until the fish is used; finally put a layer of sliced tomatoes on the top; pour over the stock in which the fish was cooked, cover with bread crumbs and some small pieces of butter, and cook in a moderate oven for twenty minutes; sprinkle the parsley over the top and serve at once.