Heat the oil in a pan, add chopped onion, grated carrot and peppers. All vegetables are fried until water evaporates. Add the minced meat, broken into small pieces, savory, black pepper and salt to taste. All stirring constantly, to not become big balls. When the mince is pozaparzhi add the cleaned and sliced ​​mushrooms and tomatoes. Allow the fire to thicken. In a baking dish, spread with butter put half the mashed potatoes on top pour mixture of minced meat and vegetables and finish again with mashed potatoes. Sprinkle with grated cheese and bake in preheated oven at 180C.