1.Wash the zucchini, remove the ends, cut them into large pieces, cook them for 5 minutes, or less if they are small, in boiling salted water, then drain them. They must remain firm
2.Coarsely mix the onions and parsley, washed and dry, mix them with the minced meat, salt, pepper and form 6 steaks of the same size.
3.Peel the red onions and slice them into thin slices.
4.Cut the round bread in their thickness, spread a layer of ketchup on 6 half pieces of bread, add the zucchini cut into thin slices, the tomatoes washed and thinly sliced, salt, pepper, and place the lettuce washed and dried.
5.Heat butter in a frying pan, as soon as it foam cook the steaks for about 4 minutes on each side over medium heat. Add butter to brown and turn them over twice.
6.Place each steak on its bread, divide the red onion rings, sprinkle the inside of the caps of the bread with the cooking juices (fat but too good), place them on the burgers, pressing hard enough with the dish of your hand to crush the meat and make the set compact. Turn over the burgers and serve immediately
