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Spaghetti Squash Au Gratin Recipe

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4.9 from 81 reviews

Spaghetti Squash Au Gratin is a comforting and creamy casserole that combines tender roasted spaghetti squash with a rich cheese sauce made from Gruyere, sharp cheddar, and Parmesan. The dish is topped with a crispy golden breadcrumb and cheese crust, making it a delicious low-carb alternative to traditional potato gratin. Perfect as a hearty side or a vegetarian main, this recipe offers a flavorful way to enjoy spaghetti squash with a decadent cheesy twist.

Ingredients

Scale

Squash

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

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

Cheese

  • 1 cup grated Gruyere cheese, divided
  • 1 cup grated sharp cheddar cheese, divided
  • 1/2 cup grated Parmesan cheese, divided

Topping

  • 1/4 cup panko breadcrumbs
  • 2 tablespoons chopped fresh parsley, for garnish (optional)

Instructions

  1. Preheat the oven: Set your oven to 400°F (200°C) to get it ready for roasting the squash and baking the gratin.
  2. Prepare the squash: Cut the spaghetti squash lengthwise into two halves. Scoop out the seeds and stringy pulp from the center to create hollow cavities.
  3. Season the squash: Brush the cut sides of each squash half generously with 2 tablespoons of melted butter, then sprinkle with salt and black pepper to taste for added flavor.
  4. Roast the squash: Place the halves cut-side down on a parchment-lined baking sheet. Roast for 45-60 minutes until the flesh is tender and can be pierced easily with a fork.
  5. Shred the squash: When cool enough to handle, use a fork to scrape and shred the flesh into spaghetti-like strands. Set aside for the sauce preparation.
  6. Melt the butter: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter to start the sauce base.
  7. Sauté the onion and garlic: Add the finely chopped onion and cook for 5-7 minutes until softened and translucent. Stir in minced garlic and sauté for an additional minute until fragrant.
  8. Make the roux: Sprinkle the flour over the onion and garlic mixture, stirring constantly for 1-2 minutes to form a smooth roux which will thicken the sauce.
  9. Whisk in the milk: Gradually add the milk a little at a time, whisking continuously to avoid lumps and achieve a smooth sauce.
  10. Simmer the sauce: Bring the sauce to a gentle simmer over medium heat, stirring constantly. Reduce to low heat and cook for 5-7 minutes until it thickens slightly.
  11. Season the sauce: Stir in salt, pepper, and nutmeg. Taste and adjust the seasoning as needed for a balanced flavor.
  12. Add the cheese: Remove from heat and incorporate 3/4 cup of Gruyere, 3/4 cup of cheddar, and 1/4 cup of Parmesan cheese. Stir until the cheese melts and the sauce becomes creamy.
  13. Combine squash and sauce: Fold the shredded spaghetti squash gently into the cheese sauce until well combined, ensuring every strand is coated.
  14. Transfer to baking dish: Pour the mixture into a greased 9×13 inch baking dish, spreading it evenly.
  15. Prepare the topping: In a small bowl, mix the remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan cheese with the panko breadcrumbs to create a crunchy topping.
  16. Sprinkle the topping: Evenly distribute the cheese and breadcrumb mixture over the top of the squash mixture in the baking dish.
  17. Bake the gratin: Place the dish in the oven and bake for 20-25 minutes until the topping is golden brown and bubbly, indicating a perfect crust.
  18. Rest before serving: Remove from the oven and allow the gratin to rest for 5-10 minutes, setting the flavors and making it easier to serve.
  19. Garnish and serve: Optionally sprinkle with fresh chopped parsley for a pop of color and fresh flavor, then serve the gratin hot and enjoy your delicious meal.

Notes

  • The baking time for the squash may vary depending on its size and oven; test doneness with a fork.
  • You can substitute whole milk with 2% milk, but whole milk provides a richer sauce.
  • For a gluten-free version, use gluten-free flour and breadcrumbs.
  • Leftovers keep well refrigerated for up to 3 days and reheat nicely in the oven.
  • To add a bit of protein, consider mixing in cooked bacon or ham before baking.
  • If you prefer a spicier dish, add a pinch of cayenne pepper or red chili flakes to the sauce.

Keywords: spaghetti squash, au gratin, cheesy casserole, roasted squash, vegetarian recipe, comfort food

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