Heat oven to 350° F.
In a heavy skillet, heat vegetable oil over medium heat; brown ground beef and onion. Add tomatoes, salt, and pepper and chili powder.
Reduce heat; simmer for 25 to 30 minutes. In a lightly greased baking dish, combine meat mixture with cooked macaroni.
Stir in 1/2 cup of the shredded cheese. Top with 1 cup buttered bread crumbs and remaining 1/2 cup shredded cheese.
Bake, uncovered, for 35 to 45 minutes, or until hot and the top is lightly browned.
Servings: 6