Preheat your oven to 375°F. Lightly grease a 9x13 baking dish.
In a large skillet over medium heat, cook the ground beef, onion, and garlic until the meat is browned and the onion is soft.
Sprinkle in the Italian seasoning, salt, and pepper. Stir in the marinara sauce and simmer for 5 minutes.
Stir the cooked pasta into the skillet mixture. Remove from heat.
Spoon half the pasta mixture into the baking dish. Top with half of the cheddar and mozzarella cheeses.
Add the remaining pasta mixture and sprinkle the rest of the cheese over the top.
Bake uncovered for 20–25 minutes, or until the cheese is bubbly and golden.
Let it sit for 5 minutes before serving so you don’t burn your tongue (speaking from experience).