First, heat a large skillet over medium-high heat.
Add the ground beef, chopped onion, and minced garlic.
Cook until the beef is fully browned and the onions are soft. Drain off any excess grease.
Next, add the cooked beef mixture to a 6-quart crockpot.
Pour in the crushed tomatoes, tomato paste, marinara sauce, and wine or broth.
Then add the salt, black pepper, sugar, oregano, thyme, dried parsley, dried basil, bay leaves, and red pepper flakes.
Stir everything together well, place the lid on the crockpot, and cook:High: 4 hours Low: 6–8 hours Once the spaghetti sauce is finished cooking, let it cool slightly while you prepare your spaghetti noodles according to package directions.
Serve the homemade spaghetti sauce over cooked spaghetti noodles and top with fresh parsley and grated Parmesan cheese if desired.
