Print

Spaghetti Squash Au Gratin Recipe

Print Recipe

★★★★★

5 from 149 reviews

Spaghetti Squash Au Gratin is a delicious and healthy twist on the classic au gratin dish, featuring tender roasted spaghetti squash strands baked in a rich, creamy cheese sauce with Gruyere, cheddar, and Parmesan cheeses. This comforting casserole is topped with a crunchy breadcrumb crust and fresh parsley garnish, perfect for a wholesome family meal or a festive side dish.

Ingredients

Scale

Spaghetti Squash

  • 1 large spaghetti squash (about 3–4 pounds)
  • 2 tablespoons unsalted butter, melted (for drizzling)
  • Salt and black pepper, to taste

Cheese Sauce

  • 2 tablespoons unsalted butter
  • 1 medium yellow onion, finely chopped
  • 2 cloves garlic, minced
  • 4 tablespoons all-purpose flour
  • 3 cups whole milk
  • 1/2 teaspoon salt, plus more to taste
  • 1/4 teaspoon black pepper, plus more to taste
  • 1/4 teaspoon nutmeg
  • 3/4 cup grated Gruyere cheese
  • 3/4 cup grated sharp cheddar cheese
  • 1/4 cup grated Parmesan cheese

Topping

  • 1/4 cup grated Gruyere cheese
  • 1/4 cup grated sharp cheddar cheese
  • 1/4 cup grated Parmesan cheese
  • 1/4 cup panko breadcrumbs

Garnish (Optional)

  • 2 tablespoons chopped fresh parsley

Instructions

  1. Preheat oven: Preheat your oven to 400°F (200°C) to prepare for roasting the spaghetti squash.
  2. Prepare the squash: Cut the spaghetti squash in half lengthwise and scoop out the seeds and stringy bits to clean the inside.
  3. Season the squash: Drizzle the cut sides of the squash with 2 tablespoons of melted butter, then sprinkle generously with salt and pepper for flavor.
  4. Roast the squash: Place the squash halves cut-side down on a baking sheet lined with parchment paper. Roast in the oven for 45-60 minutes until the flesh is tender and easily pierced with a fork.
  5. Shred the squash: Once cool enough to handle, use a fork to shred the flesh into spaghetti-like strands. Set aside for later use.
  6. Melt the butter: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter to start making the cheese sauce.
  7. Sauté the onion and garlic: Add the finely chopped onion to the melted butter and cook for 5-7 minutes until softened and translucent. Then add the minced garlic and cook for an additional minute until fragrant.
  8. Make a roux: Sprinkle the flour over the onion and garlic mixture and cook, stirring constantly, for 1-2 minutes to form the roux base for the sauce.
  9. Whisk in the milk: Gradually add the milk a little at a time, whisking continuously to avoid lumps, until the sauce is smooth and well combined.
  10. Simmer the sauce: Bring the sauce to a gentle simmer over medium heat, stirring constantly. Reduce the heat to low and simmer for 5-7 minutes until the sauce thickens slightly.
  11. Season the sauce: Stir in salt, pepper, and nutmeg, then taste and adjust seasoning as needed to balance the flavors.
  12. Add the cheese: Remove the saucepan from heat and stir in 3/4 cup Gruyere, 3/4 cup cheddar, and 1/4 cup Parmesan until the cheese melts smoothly into the sauce.
  13. Combine squash and sauce: Add the shredded spaghetti squash strands to the cheese sauce and gently stir to combine evenly.
  14. Transfer to baking dish: Pour the cheese-coated squash mixture into a greased 9×13 inch baking dish, spreading it out evenly.
  15. Prepare the topping: In a small bowl, mix the remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan, and panko breadcrumbs together.
  16. Sprinkle the topping: Evenly sprinkle the cheese and breadcrumb mixture over the top of the squash in the baking dish.
  17. Bake the au gratin: Bake in the preheated oven for 20-25 minutes, or until the topping is golden brown and bubbling.
  18. Let it rest: Remove the dish from the oven and allow it to rest for 5-10 minutes to set before serving.
  19. Garnish and serve: Garnish with chopped fresh parsley if desired, then serve hot and enjoy your healthy, cheesy Spaghetti Squash Au Gratin.

Notes

  • Make sure to roast the spaghetti squash cut-side down to help it cook evenly and retain moisture.
  • You can substitute whole milk with 2% milk for a lighter sauce, but whole milk provides a richer texture.
  • Gruyere cheese adds a distinct nutty flavor, but you can experiment with other melting cheeses such as mozzarella or fontina.
  • For a gluten-free version, substitute all-purpose flour with a gluten-free flour blend and use gluten-free breadcrumbs.
  • This dish can be prepared ahead and reheated in the oven before serving; cover with foil to prevent excessive browning.
  • Leftovers store well in the refrigerator for up to 3 days and can be gently reheated.

Keywords: spaghetti squash, au gratin, healthy casserole, cheese sauce, roasted squash, vegetarian recipe, comfort food

Find it online: https://recipeswithmia.com/spaghetti-squash-au-gratin-recipe/