In a large skillet over medium heat, add the ground beef and chopped onion. Cook for 7 to 8 minutes until the beef is browned and the onion is translucent.

Stir in the minced garlic and cook for an additional minute until fragrant.

Transfer the beef mixture to the slow cooker. Add crushed tomatoes, diced tomatoes, tomato paste, and beef broth, followed by spices.

Cover and cook on low for 6 to 8 hours or on high for 3 to 4 hours.

Stir well, serve hot, and top with cheese, sour cream, or green onions as desired.