We press the juice to the zest in a bowl, then the ground tomatoes and a teaspoon of tomato paste and stir.
Then we roll our orange on the table pressing down with our hand, in order to squeeze the juice out of it later.
Scald the orange with boiling water and rub it on a fine grater, we need the zest of about half of the orange, you can slightly more.
Cut the mackerel into 3 cm pieces.
Finely chop the onion and garlic.
Fry the onion and garlic until transparent and transfer to a separate bowl.
Pour the orange and tomato sauce into the pan, put the heat on medium and bring to a boil, stirring.
Salt and pepper to taste.
Add the fried onion and garlic and stir.