First pour boiling water over the tomatoes and then peel them. Then the skinned tomatoes are cut into small cubes.
The onions are also cut into small cubes.
Now the oil is heated in a pan. When this is hot enough, first let the onion cubes become translucent. Then add the tomato cubes and let everything become a creamy sauce over medium heat for about 15-20 minutes. First season the sauce with salt, pepper and the sugar, then add the scampis and simmer for another 5 - 10 minutes.