Rub the fillets with the garlic, 1 tablespoon of the lemon juice, and some salt and pepper. Leave for 30 minutes.
Brush a baking dish with a little olive oil and put in the cod fillets.
Melt the butter in a small frying pan and soften the shallots over a low heat so that they do not brown. Add the tomatoes and cook together for another few minutes. Pour this mixture over the cod