Double burger

Salt chopped meat, pepper, mix well. With hands wetted in cold water, form 8 flat cutlets of the same size. Fry the cutlets in melted butter on 2 sides (2-3 minutes on each side). Cut the buns into 3 parts, the middle part should be 1 cm thick. Cut the tomatoes into slices, salt, pepper, drizzle with vinegar. Wash the zucchini, dry, cut into thin slices. Grease the lower part of the buns with mayonnaise (1 tbsp per bun), put a lettuce leaf on top, a round meat cutlet on it, then slices of tomatoes. Grease with ketchup and cover with the middle part of the bun. Grease with mayonnaise, cover with salad, then another cutlet and put in slices of zucchini. Lay the tomatoes on top, grease with ketchup and cover with the top of the buns.