Cut onion into cubes and fry it until Golden in a mixture of butter (5 g) and vegetable (1 tbsp) oils. Cool.
Put the fish fillet in the bowl of a food processor.
You can use any red fish. This time I was making trout cutlets.
In the bowl of the combine with crushed fish, add potato starch (corn or rice will need one and a half times more, that is, 1.5 tbsp. l), fried onions, season the fish mass with pepper and salt. Mix the minced meat until smooth.
Finely chop the boiled prawns and mix them with soft butter (the remaining 20 grams) and chopped parsley. The weight of already peeled shrimp is given.
To form patties.
To do this, I use a serving ring with a diameter of 8 cm.
Lay a cutting Board with parchment, put a serving ring on it, put about 50 grams of minced fish in it, flatten and flatten the minced meat with a spoon, make a small depression in the middle. Put a teaspoon of prawns with herbs in this recess.
Put another 50 grams of minced fish on the shrimps, lightly press (tamp) with a spoon.
Carefully remove the ring.
Put the formed cutlets in the freezer for 30-40 minutes. The oil in the cutlets will "catch" a little and will not leak out during frying.
It is very convenient to prepare such cutlets in advance, and an hour and a half before serving, get them out of the freezer, fry them and serve them to the table.
Fry the cutlets in well-heated vegetable oil over a moderate heat. Three or four minutes on one side...
... then turn over, fry for another minute, reduce the heat to low, cover the pan with a lid and cook the cutlets for another five minutes.
Everything is ready!