Clean the mushrooms, possibly wash and slice them. Clean, wash and cut the peppers into strips. Dab the meat dry and also cut into strips. Peel and finely chop the onion.
Heat 2 tablespoons of oil in a frying pan. Fry the meat in portions on all sides over a high heat. Season with salt and pepper and remove. Heat 1 tablespoon of oil in the frying fat. Sauté the mushrooms in it. Add paprika and onion and fry for about 2 minutes. Season with salt, pepper and 1⁄2 TL paprika powder. Add stock and stir in mustard. Bring to the boil and simmer for about 5 minutes.
Stir sour cream and starch until smooth. Stir the mixture into the sauce. Add the meat and simmer for about 3 minutes. Wash the dill, shake dry and chop finely. Season to taste with salt and pepper. Sprinkle with dill. Serve with rice or bread.