Preheat your oven to 350°F (175°C).

Cook macaroni according to package instructions, drain, and set aside.

In a large pot, cook ground beef, onion, and bell pepper over medium heat until beef is browned; drain excess fat.

Stir in tomato sauce and macaroni, mixing well.

Transfer mixture to a greased baking dish and top with cheese.

Bake in preheated oven for about 20–25 minutes, until cheese is melted and bubbly.

Let cool for 5 minutes before serving.