Preheat the oven to 375 degrees Fahrenheit.
Cook the beef in a skillet over medium heat until browned, using a spatula to break it into pieces.
12 ounces ground beef
In a large baking dish, add the uncooked spaghetti. Drizzle the olive oil on top, and gently rub it over the pasta until it is completely coated. (This helps prevent the spaghetti from sticking together.)
16 ounces spaghetti, ¼ cup olive oil
Add all the ingredients to a 9x13 baking dish except for the Parmesan cheese. Stir to combine.
1 16 ounce jar pasta sauce, ½ yellow onion, ½ cup red bell peppers, ½ cup green bell peppers, ½ cup fresh Italian parsley, ½ cup fresh basil, 3 cups broth, 1 teaspoon dried oregano, 1 teaspoon salt or to taste, 1 teaspoon black pepper or to taste, 5 cloves garlic
Cover, and bake 45-50 minutes or until the meat is cooked through, the veggies are tender, and the spaghetti is al dente, stirring halfway through.
Garnish with Parmesan cheese, and serve warm.
1 cup Parmesan cheese shavings for garnish
Store the sauce separately from the spaghetti in an airtight container in the fridge for up to 3 days.