In a large pan or skillet, combine the ground beef, garlic powder, Italian seasoning, and red pepper flakes. Cook the beef over medium-high heat for about 7 minutes, or until it is no longer pink in the middle.
Once the beef is fully cooked, add the diced onion. Continue to cook the mixture for about 5 minutes, or until the onions are soft and begin to turn translucent.
Stir in the marinara sauce, ensuring it evenly coats the ground beef.
Add the beef mixture to a 9x13 inch baking dish along with the spaghetti and 2 cups of cheese. Fold to combine.
Top the dish with the remaining cheese and bake uncovered for 25 minutes, or until bubbly.
Serve and enjoy!
Notes
We usually use 90/10 ground beef, but you are welcome to use any kind. If you use anything with a higher fat content then you will need to drain some of the excess grease from the pan.
You can store your leftover baked spaghetti in the fridge for up to 4 days in an airtight container. Reheat your leftovers by placing a single serving on a plate covered with a paper towel or paper plate. Microwave for 1 minute, or until the spaghetti is warm all the way through.
We like to serve this spaghetti with some homemade garlic bread and a freshly made Caesar salad.
You can replace the white onion with a yellow onion.
You can make your own Italian seasoning by combining equal parts dried oregano, dried basil, garlic salt, onion powder, and dried thyme.
We usually use plain marinara sauce, but you are welcome to use your favorite red sauce. This can be a fun way to add a slightly different flavor to the dish. In addition to using mozzarella cheese, you can also add ½ cup of Parmesan cheese to the top of your baked spaghetti.