Go Back
Parmesan Spaghetti Squash Gratin

Parmesan Spaghetti Squash Gratin

A creamy, cheesy Parmesan Spaghetti Squash Gratin made with tender roasted spaghetti squash, garlic, butter, heavy cream, and plenty of freshly grated Parmesan. Baked until bubbling and golden, this comforting vegetarian side dish delivers tender squash strands, a rich creamy center, and an irresistibly crisp, savory cheese topping.
Print Recipe Pin Recipe
Prep Time 20 minutes
Cook Time 55 minutes
Chill Time 10 minutes
Total Time 1 hour 25 minutes
Servings: 6
Course: Main Course, Side Dish
Cuisine: American, Italian-Inspired
Calories: 330
Ingredients Equipment Method Notes

Ingredients
  

  • For the Spaghetti Squash
  • 1 medium spaghetti squash approximately 3–4 pounds
  • 1 tablespoon olive oil
  • ½ teaspoon salt
  • ¼ teaspoon freshly ground black pepper
  • For the Creamy Parmesan Sauce
  • 2 tablespoons unsalted butter
  • 3 cloves garlic finely minced
  • 1 cup heavy cream
  • 1 cup freshly grated Parmesan cheese divided
  • ½ cup shredded mozzarella cheese optional
  • ¼ teaspoon freshly ground black pepper
  • Salt to taste
  • 2 tablespoons fresh parsley finely chopped

Equipment

  • Large baking sheet
  • Sharp chef's knife
  • Large spoon
  • Fork
  • Large mixing bowl
  • Medium saucepan
  • Wooden spoon or whisk
  • 9 × 13-inch baking dish or similar oven-safe casserole dish
  • Measuring cups and spoons
  • Grater for Parmesan
  • Tongs or large serving spoon

Method
 

  1. Roast the Spaghetti Squash
  2. Preheat the oven to 400°F (200°C).
  3. Carefully cut the spaghetti squash in half lengthwise. Scoop out and discard the seeds and loose fibrous strands from the center.
  4. Brush the cut sides lightly with olive oil and season with salt and black pepper. Place the squash cut-side down on a baking sheet.
  5. Roast for approximately 35–50 minutes, depending on the size of the squash, until the flesh is tender and can be easily separated with a fork.
  6. Make the Squash Strands
  7. Remove the roasted squash from the oven and allow it to cool for several minutes until it is safe to handle.
  8. Turn the squash halves cut-side up. Using a fork, gently scrape the flesh lengthwise to create spaghetti-like strands.
  9. Transfer the strands to a large mixing bowl. If the squash seems particularly wet, allow the strands to drain briefly to remove excess moisture.
  10. Prepare the Parmesan Sauce
  11. Melt the butter in a medium saucepan over medium-low heat.
  12. Add the minced garlic and cook for about 30–60 seconds, stirring frequently, until fragrant. Do not allow the garlic to burn.
  13. Pour in the heavy cream and gently warm it.
  14. Gradually add about ¾ cup of the grated Parmesan, stirring continuously until melted and incorporated into a smooth, creamy sauce.
  15. Season with black pepper and taste before adding additional salt, since Parmesan is naturally salty.
  16. Combine the Squash and Sauce
  17. Pour the creamy Parmesan sauce over the spaghetti squash strands.
  18. Using tongs or a large spoon, gently toss until the squash is evenly coated. Avoid vigorous stirring so the strands remain intact.
  19. If using mozzarella, you can stir a small amount into the mixture for extra creaminess and reserve the rest for the topping.
  20. Assemble the Gratin
  21. Lightly grease a 9 × 13-inch baking dish or similarly sized oven-safe casserole dish.
  22. Transfer the creamy spaghetti squash mixture into the dish and spread it into an even layer.
  23. Sprinkle the remaining Parmesan over the top. Add the mozzarella if using.
  24. Bake Until Golden
  25. Place the baking dish in the 400°F (200°C) oven and bake for approximately 10–15 minutes, or until the cheese is melted, bubbling, and lightly golden.
  26. For a deeper golden crust, place the gratin under the broiler for 1–2 minutes at the end. Watch it closely to prevent the cheese from burning.
  27. Rest and Serve
  28. Remove the gratin from the oven and allow it to rest for 5–10 minutes.
  29. Garnish with freshly chopped parsley and serve warm.

Notes

For the best texture: Avoid overcooking the spaghetti squash. It should be tender enough to separate into strands while still retaining some structure.
Control moisture: If your squash releases a lot of water, let the strands drain briefly before mixing them with the sauce.
Use freshly grated Parmesan: It melts more smoothly and provides better flavor than many pre-shredded varieties.
Watch the salt: Parmesan is naturally salty, so taste the sauce before adding extra salt.
For extra browning: Broil the assembled gratin for 1–2 minutes at the end, watching carefully.
Make ahead: The roasted squash and Parmesan sauce can be prepared separately up to 1 day ahead and refrigerated. Assemble and bake when ready.
Storage: Refrigerate leftovers in an airtight container for up to 3–4 days.
Reheating: Reheat gently in the oven or microwave. For the best texture, use the oven and uncover during the final few minutes.
Vegetarian: This recipe is vegetarian, although strict vegetarians should check the Parmesan label for the type of rennet used.
Gluten-free: The basic recipe is naturally gluten-free, but check packaged ingredients if gluten contamination is a concern.
Low-carb: Spaghetti squash is lower in carbohydrates than traditional pasta, making this a lighter alternative to conventional pasta gratins. Exact carbohydrate content depends on serving size.
Keto: Whether it fits a strict ketogenic diet depends on the portion size and the individual's carbohydrate target.