Knead minced meat with quark, breadcrumbs, 1 teaspoon mustard and parsley. Season with salt and pepper. Form a flat meatball from the mixture. Fry in hot oil for about 3 minutes on each side
Mix salad cream and 1/2 tsp. mustard. Wash tomato and cucumber, cut into slices. Wash lettuce leaves and shake dry
Cut the buns in half. Spread the bottom half with mustard cream. Cover with lettuce leaves, meatball, tomato and cucumber. Spread the upper half of the roll with ketchup and place on top