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Spaghetti Squash Au Gratin Recipe

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★★★★★

4.5 from 141 reviews

This Spaghetti Squash Au Gratin offers a deliciously creamy and cheesy twist on a healthy vegetable base. Roasted spaghetti squash strands are enveloped in a rich Gruyere, cheddar, and Parmesan cheese sauce, then baked with a crunchy panko breadcrumb topping. It’s a comforting, low-carb alternative to traditional au gratin dishes, perfect as a side or a main for those seeking a nutritious yet indulgent meal.

Ingredients

Scale

Spaghetti Squash

  • 1 large spaghetti squash (about 3–4 pounds)
  • 2 tablespoons unsalted butter, melted (for squash)
  • Salt and freshly ground 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
  • 1/4 teaspoon black pepper
  • 1/4 teaspoon ground 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

  • 2 tablespoons chopped fresh parsley (optional)

Instructions

  1. Preheat the oven: Set the oven to 400°F (200°C) to ensure it reaches the perfect temperature for roasting the squash and baking the au gratin.
  2. Prepare the squash: Cut the spaghetti squash in half lengthwise and scoop out the seeds and fibrous strands from the center to create clean halves ready for roasting.
  3. Season the squash: Drizzle the cut sides of the squash with 2 tablespoons of melted butter, and generously season with salt and pepper to enhance flavor during roasting.
  4. Roast the squash: Place the squash halves cut-side down on a parchment-lined baking sheet and roast for 45-60 minutes until the flesh is tender and easily pierced with a fork.
  5. Shred the squash: Once the squash is cool enough to handle, use a fork to scrape out the flesh into spaghetti-like strands and set aside.
  6. Melt butter for sauce: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter to start the cheese sauce base.
  7. Sauté onion and garlic: Add the finely chopped onion to the melted butter and cook for 5-7 minutes until softened and translucent. Stir in minced garlic and cook for another minute until fragrant.
  8. Make the roux: Sprinkle the flour over the onion and garlic mixture and cook while stirring constantly for 1-2 minutes, which helps thicken the sauce later.
  9. Whisk in milk: Gradually pour in the milk, whisking continuously to avoid lumps and achieve a smooth sauce consistency.
  10. Simmer the sauce: Bring the sauce to a gentle simmer, stirring constantly, then reduce heat to low and cook for 5-7 minutes until it thickens slightly.
  11. Season the sauce: Stir in salt, black pepper, and nutmeg. Taste and adjust seasoning if necessary to balance the flavors.
  12. Add cheeses: Remove the saucepan from heat and fold in 3/4 cup Gruyere, 3/4 cup cheddar, and 1/4 cup Parmesan until the cheese melts into a smooth, creamy sauce.
  13. Combine squash with sauce: Gently stir the shredded spaghetti squash into the cheese sauce until well combined.
  14. Transfer to baking dish: Pour the mixture into a greased 9×13 inch baking dish, spreading it evenly.
  15. Prepare topping: In a small bowl, mix together the remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan, and panko breadcrumbs for a flavorful crispy topping.
  16. Sprinkle topping: Evenly distribute the cheese and breadcrumb mixture over the surface of the squash casserole.
  17. Bake au gratin: Place the dish in the preheated oven and bake for 20-25 minutes until the topping is golden brown and bubbly.
  18. Rest before serving: Remove from the oven and let rest for 5-10 minutes to set the dish and enhance flavors.
  19. Garnish and serve: Optionally sprinkle with fresh chopped parsley, then serve hot and enjoy this creamy, cheesy, healthy casserole.

Notes

  • To easily remove seeds from spaghetti squash, use a spoon and scrape gently.
  • For a lighter version, substitute low-fat milk and reduce cheese quantities.
  • Panko breadcrumbs add extra crunch—regular breadcrumbs can be used but with less crispiness.
  • Allowing the au gratin to rest after baking helps it firm up, making serving easier.
  • This dish can be prepared ahead up to the baking step and refrigerated, then baked before serving.

Keywords: spaghetti squash au gratin, cheesy spaghetti squash, healthy au gratin recipe, vegetarian casserole, low-carb comfort food

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