Pour the oil into a hot frying pan and spoon the minced Turkey. It is desirable that the cutlets are the same diameter as the bun in which we will "sculpt" the hamburger. But I did it in a pan for pancakes, so the cutlets are more or less even, but the diameter was smaller.
Fry the cutlets on medium heat on both sides for about 12 minutes.
We take a hamburger bun, I have a ready-made one with sesame seeds. With a knife (preferably with a file), cut lengthwise into three equal parts.
Dry the bread in a grill pan, all parts except the top and bottom.
Preparing the sauce. Mix mayonnaise, ketchup and mustard with grains.
You can, of course, make hamburgers in advance at home, but then they will get wet. Therefore, I recommend collecting it on a picnic. Grease the dried (toasted) sides of the bread with plenty of sauce.
On the lower part, put the pickled onion on the sauce.
Next, put the tomato cut into rings.
Then the lettuce.
Cover with the middle part of the loaf, it should be greased on both sides.