Gut the mackerel, wash it well and dry it. Season with salt and pepper, drizzle with lemon juice and olive oil.
Wash the garlic head, remove the top husk and cut off the top a little. Pour olive oil over the slices.
To wrap the fish and garlic in the foil.
Put to bake in a preheated 200 degree oven for 20-25 minutes. Turn off the oven and leave to cool.
Cut the mackerel into small pieces by removing the skin and selecting the bones. Remove the baked garlic cloves from the husk and mash with a fork.
Prepare olives and capers.
Chop the olives and capers and add to the mackerel. Add the lemon juice. Stir. If there is not enough salt or pepper, add to taste.
Add 2-3 tablespoons of softened butter and mix gently. Mackerel is quite an oily fish, so you can decide for yourself about the oil.
Put the riyet in a jar and send it to the refrigerator. In a day, if you don't eat it earlier, the riyet will be tastier and richer.