Spaghetti Squash Casserole

1 spaghetti squash
1 pound ground beef
1 small onion, chopped
2 garlic cloves, minced
1 14.5 oz can can diced tomatoes
¼ cup tomato paste
1/2 teaspoon dried oregano
sea salt and black pepper to taste
1 ½ cups shredded mozzarella cheese

1. Heat oven to 400°F. Cut squash in half lengthwise and scoop out seeds. Place cut side down in a baking dish and add ½ cup of water. Bake for about 45 minutes or until easily pierced with a fork. Reduce oven to 350. Remove squash  from oven and let cool; scoop squash out of shell, separating the strands with a fork. Spread in a greased 1 ½ quart baking dish.
2. While squash is baking, cook beef, onion, and garlic until meat is browned and onion is tender, about 10 minutes. Add tomatoes, tomato paste, oregano, salt, and pepper. Bring to a boil, reduce heat, and cook for 5 minutes. Spread sauce over squash, sprinkle with the cheese, and bake, uncovered, at 350°F for 25 minutes or until lightly browned and bubbly. Serves 6.