To prepare the stewed cod, begin with the sauce: in a non-stick skillet, add the tomato passata, a clove of garlic, and a drizzle of olive oil. (For this recipe, the garlic is not sautéed first, but you may do so if you prefer.)
Cook over low heat for 20 minutes.
Add the cod fillets, olives, and well-rinsed and squeezed capers (be mindful of the amount of capers, as they can make the dish very salty).
Cover with a lid and cook for another 20 minutes over low heat, gently turning the fillets halfway through cooking.
Garnish with freshly chopped parsley and black pepper before serving.