Clean, wash and cut the peppers into strips. Cut the skin of the tomatoes into a cross shape, blanch with boiling water, rinse with cold water and remove the skin. Cut the tomatoes into large pieces.
Peel and chop the onions and garlic. Heat 1 tablespoon of oil in a frying pan and sauté the onions and garlic. Add the tomatoes and ##laurel## and simmer for about 3 minutes. Add stock, stir in tomato paste.
Add the peppers and simmer for another 6-8 minutes. Season to taste with salt, pepper, sugar, paprika powder and vinegar. Wash the meat, dab dry and season with salt and pepper. Heat 2 tablespoons of oil in a frying pan.
Sauté the meat on both sides for 2-3 minutes and cook in the preheated oven (electric range: 150 °C/ convection oven: 125 °C/ gas: level 1) for 8-10 minutes until medium rare. In the meantime, wash liver, dab dry and turn in flour.
Heat 1 tablespoon of oil in a frying pan. Fry the liver on each side for about 2 minutes. Take it out, season with salt and pepper. Arrange Letscho with ##beef## fillet and liver on a plate.
Parsley potatoes or baguette taste good with it.