Knead minced meat, 1 egg and breadcrumbs. Season with salt, pepper, paprika powder and cumin. Form 6 round patties from the minced meat mixture. Heat 2 tablespoons of oil in a frying pan. Fry the patties for about 4 minutes, turning them over. Take them out. Leave the bacon slices in the hot frying oil until crispy. Take out and let them drip off on kitchen paper.
Onions peel, quarter and in columns cut. Heat butter in a pan. Fry the onion slices in it. Sprinkle with 2 tablespoons of sugar and allow to caramelize. Deglaze with balsamic vinegar and simmer for 3-5 minutes.
Grate cheese. Mix sour cream and 4 eggs. Season with salt and pepper. Spread the bottom halves of the rolls with 100 ml barbecue sauce. Put the bread roll halves into an ovenproof dish (approx. 25 x 40 cm). Place the patties on the roll halves and cover with caramelized onions. Break the bacon into pieces and spread on the patties. Sprinkle with 100 g grated cheese. Drizzle 50 ml barbecue sauce over it. Place the top halves of the rolls on top. Pour over the top. Sprinkle with 50 g grated cheese. Cover with foil. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 25 minutes. Remove foil. Bake the burgers for another 8-10 minutes.
Peel and chop the red onion. Wash, clean and chop the tomatoes. Finely dice the cucumbers. Clean, wash and cut lettuce into fine strips. Mix cider vinegar, 1 tsp. sugar, salt and pepper. Stir in 2 tablespoons of oil. Mix salad, diced tomatoes and vinaigrette. Take the casserole out of the oven and serve. Sprinkle with some lettuce. Serve the remaining lettuce with it.