Cut the spaghetti squash in half lengthwise and scoop out the seeds. Place the halves cut-side down on a baking sheet and bake for 30-40 minutes, until tender.
While the squash is baking, cook the ground beef in a skillet over medium heat until browned. Drain any excess fat.
Add the marinara sauce, Italian seasoning, salt, and pepper to the skillet with the ground beef. Stir to combine and let it simmer for a few minutes.
Once the squash is done, use a fork to scrape out the strands into a large bowl. Add the beef mixture and half of the mozzarella cheese. Mix well.
Transfer the mixture to a baking dish and top with the remaining mozzarella cheese. Bake for another 10-15 minutes, until the cheese is melted and bubbly.
Let it cool for a few minutes before serving. Enjoy!
Notes:
You can add more vegetables like bell peppers or spinach for extra nutrition.