Brown the ground beef and drain off any grease.
Chop the onion, garlic and bell pepper.
Warm the olive oil in a large skillet. Sauté the onion, garlic and bell pepper until soft.
Add the ground beef.
Add the tomatoes, tomato sauce and tomato paste. Stir well.
Add the bay leaf, marjoram, basil, oregano, and thyme. Add the salt and pepper. Stir well.
Simmer for 15-20 minutes, then taste. Adjust the seasonings if desired. Cook for an additional 30-45 minutes, stirring occasionally.
Serve over freshly cooked spaghetti.