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Spaghetti Squash Au Gratin Recipe

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4.7 from 117 reviews

This Spaghetti Squash Au Gratin is a comforting and cheesy baked dish featuring tender roasted spaghetti squash strands smothered in a creamy Gruyere, sharp cheddar, and Parmesan cheese sauce, topped with a golden breadcrumb crust. Perfect as a delicious, low-carb alternative to traditional potato au gratin, it makes a satisfying side or vegetarian main course.

Ingredients

Scale

Squash

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

Sauce

  • 4 tablespoons unsalted butter, divided
  • 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 the oven: Heat your oven to 400°F (200°C) to prepare for roasting the squash and baking the au gratin.
  2. Prepare the squash: Slice the spaghetti squash lengthwise and scoop out the seeds and stringy bits to create space for roasting.
  3. Season the squash: Drizzle the cut sides with 2 tablespoons of melted butter and season with salt and pepper generously for flavor.
  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: Allow the roasted squash to cool. Then, use a fork to scrape and shred the flesh into spaghetti-like strands. Set aside.
  6. Melt butter for sauce: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter carefully without browning.
  7. Sauté the onion and garlic: Add the finely chopped onion to the melted butter and cook until it becomes translucent and soft, about 5-7 minutes. 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. Stir continuously for 1-2 minutes to cook the flour without browning, creating a roux to thicken the sauce.
  9. Whisk in milk: Slowly add the milk in small increments while whisking to avoid lumps, ensuring a smooth sauce base.
  10. Simmer the sauce: Bring the mixture to a simmer over medium heat while stirring constantly. Reduce heat to low and simmer 5-7 minutes until the sauce thickens slightly.
  11. Season the sauce: Stir in salt, black pepper, and nutmeg. Taste and adjust seasoning as preferred.
  12. Add cheese to sauce: Remove the sauce from heat. Stir in 3/4 cup each of Gruyere and sharp cheddar cheeses, and 1/4 cup Parmesan until melted and the sauce is creamy and smooth.
  13. Combine squash and sauce: Gently fold the shredded spaghetti squash strands into the cheese sauce until well coated.
  14. Transfer to baking dish: Pour the cheesy squash mixture into a greased 9×13-inch baking dish, spreading evenly.
  15. Prepare the topping: In a small bowl, mix the remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan cheeses, and panko breadcrumbs to create a crunchy topping.
  16. Sprinkle the topping: Evenly distribute the cheese and breadcrumb topping over the surface of the squash mixture for a golden crust.
  17. Bake the au gratin: Place in the preheated oven and bake for 20-25 minutes until the topping turns golden brown and bubbly.
  18. Let it rest: Remove from the oven and allow to rest for 5-10 minutes to set and cool slightly for easier serving.
  19. Garnish and serve: Optionally sprinkle freshly chopped parsley over the top. Serve hot and enjoy this creamy, cheesy spaghetti squash au gratin.

Notes

  • Make sure to roast the spaghetti squash until very tender; this makes shredding easier and enhances texture.
  • For a lighter version, substitute whole milk with 2% milk, though the sauce may be less creamy.
  • Panko breadcrumbs add a nice crispy texture; for gluten-free, use gluten-free breadcrumbs.
  • Gruyere and sharp cheddar provide great flavor depth, but you can substitute with other melting cheeses as preferred.
  • This dish can be prepared a day ahead and baked just before serving; cover tightly and store refrigerated.

Keywords: Spaghetti Squash Au Gratin, cheesy spaghetti squash, roasted squash recipe, vegetarian au gratin, low-carb side dish

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