Preheat the oven to 350 degrees F (175 degrees C).
Crumble the ground beef into a large skillet over medium-high heat. Cook, stirring frequently, until evenly browned. Drain.
Bring a large pot of lightly salted water to a boil. Add macaroni, and cook until tender, about 8 minutes. Drain, and stir in butter. Transfer to a large casserole dish, and mix in the ground beef, tomato sauce, and Cheddar cheese. Sprinkle a little salt and pepper over the top.
Bake uncovered for 30 minutes in the preheated oven, or until heated through and bubbly.
