In a large skillet, brown the ground beef and onions together, breaking up the beef until it's cooked and the onions are soft.
Add minced garlic and cook for 1 minute, until fragrant.
Stir in the garlic powder, Italian seasoning, salt, and black pepper. Pour in the tomato sauce. Bring to a simmer and cook for 20 minutes, stirring occasionally.
Meanwhile, bring a large pot of water to a boil, and cook the elbow macaroni according to the package directions.
Drain the pasta, then add it to the sauce, tossing until everything is well combined. Serve immediately.