Step 1

Heat a Dutch oven over medium-high heat. Cook and stir ground beef, onion, and garlic until beef is browned and crumbly and onion is translucent, 5 to 7 minutes. Drain and discard excess grease.

Step 2

Stir in tomato sauce, diced tomatoes, water, chili powder, oregano, and black pepper. Bring to a boil. Cover, reduce heat, and let simmer, stirring often, for about 30 minutes.

Step 3

Break spaghetti into thirds and add to the pot; cover and simmer, stirring often, until pasta is tender, about 20 minutes. Serve topped with Parmesan cheese.