Boil rice (I use the machine for rice, but if you do - in a saucepan). In a separate pot fry gently in the butter finely chopped onion, grated carrot and celery, minced meat and chopped mushrooms add a little hot water and stew under cover about 3-4 minutes. Add to mixture and suffocating already cooked rice and a little water. Put spices (amount - according to your personal taste), stir everything well. Cut the sweet bell peppers in half and arrange them in a buttered baking dish. In the three halves peppers, whose bottom has a hole put in a round slice of tomato. Stuff the peppers with the meat-rice mixture. If there are remaining tomato slices - put them on the filled peppers, which have their bottom. Pour 1-2 fingers of water at the bottom of the pan and bake in a preheated oven.