Bring a large pot of salted water to a boil. Add elbow macaroni and cook until al dente, 8-10 minutes. Drain and set aside.

In a skillet, add chopped onion and ground beef. Cook for 5-10 minutes until beef is browned and onions are tender.

Stir in condensed tomato soup and let it simmer for about 5 minutes.

Fold in the drained macaroni into the skillet. Cook for 2-3 minutes over low heat.

Season with salt and pepper. Serve warm, optionally topping with shredded cheese and broil until bubbly.