6 red tomatoes
2 medium onions
teaspoon of dried thyme or 5 or 6 sprigs of fresh thyme
1 tbsp of wine vinegar
3 tbsp of olive oil (pomace is fine)
black pepper and salt to taste
6 mackerel fillets (Note: the mack fillets I am talking about are the ones they get in England, from fish about 30 to 35 centimetres long NOT the spanish mackerel they get in Australia that are about a metre long!)
Preheat the oven to 170 degrees centigrade.
Mix together half the olive oil and all the ingredients except the mackerel and spread the mixture on the bottom of a baking tray that is big enough to accomodate the mackerel fillets in a single layer.
Lay the mackerel fillets, skin up, on the top of the mixture, drizzle the rest of the olive oil over the mackerel and also salt and pepper.
Cover the mackerel with aluminium foil and bake for 20 minutes.
Remove foil and bake, uncovered, for another 5 minutes.