Spaghetti Squash Casserole (Low Carb, Gluten-Free)

Spaghetti squash is a low-carb, nutrient-dense alternative to pasta, and in this Spaghetti Squash Casserole, it takes center stage in a rich, cheesy, and comforting dish that feels indulgent but is secretly packed with wholesome ingredients.

Roasted spaghetti squash forms the perfect base for a creamy, garlicky tomato sauce and plenty of melty cheese, creating a dish that’s both satisfying and naturally gluten-free.

This casserole is a great meal prep option since it stores and reheats beautifully. Whether you’re looking for a keto-friendly pasta alternative, a meatless main dish, or just a cozy casserole to enjoy on a chilly night, this recipe is a must-try!

Why You’ll Love This Recipe

• Naturally gluten-free and low-carb but still incredibly satisfying
• Easy to make and packed with flavor
• Rich, cheesy, and comforting without being too heavy
• A great way to use up spaghetti squash
• Meal-prep friendly and reheats well

Ingredients

• 1 large spaghetti squash
• 1 tablespoon olive oil
• ½ teaspoon salt
• ½ teaspoon black pepper
• ½ teaspoon garlic powder
• ½ teaspoon dried oregano
• 1 small onion, diced
• 3 cloves garlic, minced
• 1 (14.5 oz) can crushed tomatoes
• ½ teaspoon red pepper flakes (optional)
• ½ teaspoon Italian seasoning
• ½ cup ricotta cheese
• 1 cup shredded mozzarella cheese
• ½ cup grated Parmesan cheese
• 2 tablespoons chopped fresh basil (for garnish)

Instructions

1. Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
2. Cut the spaghetti squash in half lengthwise and scoop out the seeds. Drizzle with olive oil, salt, black pepper, and garlic powder. Place cut side down on the baking sheet and roast for 35-40 minutes, or until the squash is tender and can be easily shredded with a fork.
3. While the squash is roasting, heat olive oil in a skillet over medium heat. Add diced onion and cook for 3-4 minutes, then stir in minced garlic, crushed tomatoes, red pepper flakes, and Italian seasoning. Simmer for 10 minutes, stirring occasionally.
4. Once the spaghetti squash is done, use a fork to shred the flesh into spaghetti-like strands and transfer to a large mixing bowl.
5. Stir in the tomato sauce mixture and ricotta cheese, then transfer everything to a lightly greased 9×13-inch baking dish.
6. Sprinkle shredded mozzarella and Parmesan cheese over the top.
7. Bake uncovered at 375°F (190°C) for 20 minutes, or until the cheese is melted and bubbly.
8. Let cool slightly before garnishing with fresh basil and serving.

Nutritional Info (per serving, serves 6):

Calories: ~280
Protein: ~14g
Carbs: ~18g
Fat: ~16g

Chef’s Tips

• For a creamier texture, add ½ cup of heavy cream to the sauce.
• Make it vegan by using dairy-free cheese and replacing ricotta with cashew cream.
• Want extra protein? Stir in shredded cooked chicken or ground turkey before baking.
• Spaghetti squash can be prepped ahead! Roast it in advance and store the strands in the fridge for up to 5 days.
• Add extra veggies like mushrooms, spinach, or zucchini for even more nutrients.