Brown the Hamburger in the butter and add the onions and garlic. Stir in the tomato sauce, salt and pepper. Combine the sour cream, cheese and carrots. Add the combination to the noodles and mix. Alternate layers of the meat mixture and the noodle mixture in a 3-quart casserole, beginning and ending with the noodle mixture. Top with the cheddar cheese. Bake at 350 degrees F. for at least 45 minutes and serve hot.