Spaghetti Squash Au Gratin Recipe

Introduction

Spaghetti Squash Au Gratin is a comforting twist on a classic dish, featuring tender roasted spaghetti squash strands baked in a creamy, cheesy sauce. It’s perfect for a cozy dinner that feels indulgent yet wholesome.

Ingredients

• 1 large spaghetti squash (about 3-4 pounds)
• 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
• 1 cup grated Gruyere cheese, divided
• 1 cup grated sharp cheddar cheese, divided
• 1/2 cup grated Parmesan cheese, divided
• 1/4 cup panko breadcrumbs
• 2 tablespoons chopped fresh parsley, for garnish (optional)

Instructions

1. Step 1: Preheat your oven to 400°F (200°C). Cut the spaghetti squash in half lengthwise and scoop out the seeds and stringy bits.
2. Step 2: Drizzle the cut sides of the squash with 2 tablespoons of melted butter, then sprinkle generously with salt and pepper.
3. Step 3: Place the squash halves cut-side down on a baking sheet lined with parchment paper. Roast for 45-60 minutes until the flesh is tender and easily pierced with a fork.
4. Step 4: When cool enough to handle, use a fork to shred the squash flesh into spaghetti-like strands and set aside.
5. Step 5: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter.
6. Step 6: Add the chopped onion and cook until softened and translucent, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant.
7. Step 7: Sprinkle the flour over the onion and garlic mixture and cook, stirring constantly, for 1-2 minutes to form a roux.
8. Step 8: Gradually whisk in the milk, a little at a time, ensuring there are no lumps, until the sauce is smooth.
9. Step 9: Bring the sauce to a simmer, then reduce heat to low and simmer for 5-7 minutes until slightly thickened.
10. Step 10: Stir in salt, pepper, and nutmeg. Taste and adjust seasonings as needed.
11. Step 11: Remove the saucepan from heat and stir in 3/4 cup Gruyere, 3/4 cup cheddar, and 1/4 cup Parmesan cheese until melted and creamy.
12. Step 12: Gently fold the shredded spaghetti squash into the cheese sauce.
13. Step 13: Pour the mixture into a greased 9×13 inch baking dish.
14. Step 14: In a small bowl, combine the remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan, and panko breadcrumbs to make the topping.
15. Step 15: Sprinkle the topping evenly over the squash mixture.
16. Step 16: Bake for 20-25 minutes until the topping is golden and bubbly.
17. Step 17: Let the dish rest for 5-10 minutes before serving. Garnish with fresh parsley if desired, then enjoy!

Tips & Variations

• Don’t overcook the spaghetti squash to avoid mushy strands; it should be tender but still slightly firm.
• Use high-quality cheeses for a richer flavor and smoother sauce.
• Add a pinch of red pepper flakes to the sauce for a subtle spicy kick.
• Boost the dish by mixing in cooked bacon, ham, or sausage with the squash and cheese sauce.
• Try different cheeses like mozzarella or fontina to vary the taste and texture.
• Ensure the Parmesan cheese is vegetarian-friendly if required, as some varieties use animal rennet.

Storage

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350°F (175°C) until warmed through to maintain the crispy topping. The au gratin can also be assembled ahead and refrigerated for up to 24 hours before baking; add a few extra minutes to the baking time if baked from cold.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I use a different type of squash for this recipe?

Spaghetti squash is unique because it shreds into strands resembling pasta. Other squashes won’t achieve the same texture, but you can experiment with roasting and mashing butternut or acorn squash for a different style of gratin.

How do I know when the spaghetti squash is done roasting?

The squash is ready when the flesh can be easily pierced with a fork and pulls apart in spaghetti-like strands. The skin should be tender but firm enough to handle safely.

Spaghetti Squash Au Gratin Recipe

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4.7 from 59 reviews

Spaghetti Squash Au Gratin is a comforting and creamy baked casserole that replaces traditional potatoes with nutritious spaghetti squash. Roasted until tender, the squash is combined with a rich cheese sauce made from Gruyere, sharp cheddar, and Parmesan, then topped with a golden, crispy breadcrumb and cheese crust. This dish offers a delicious, lower-carb alternative to classic gratins, perfect for a cozy family dinner or special occasion.

• Author: Ella
• Prep Time: 15 minutes
• Cook Time: 1 hour 15 minutes
• Total Time: 1 hour 30 minutes
• Yield: 6–8 servings 1x
• Category: Main Course
• Method: Baking
• Cuisine: American
• Diet: Vegetarian

Ingredients

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Spaghetti Squash

• 1 large spaghetti squash (about 3–4 pounds)
• 2 tablespoons unsalted butter, melted (for seasoning squash)
• 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

• 2 tablespoons chopped fresh parsley (optional)

Instructions

1. Preheat Oven: Set 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 carefully.
3. Season the Squash: Drizzle 2 tablespoons of melted butter over the cut sides of the squash and season generously with salt and black pepper.
4. Roast the Squash: Place the squash halves cut-side down on a baking sheet lined with parchment paper. Roast for 45-60 minutes until the flesh is tender and easily pierced with a fork.
5. Shred the Squash: After the squash cools enough to handle, use a fork to scrape the flesh into spaghetti-like strands. Set aside.
6. Melt Butter: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter.
7. Sauté Onion and Garlic: Add the finely chopped onion and cook for 5-7 minutes until softened and translucent. Add minced garlic and cook another minute until fragrant.
8. Make Roux: Sprinkle the flour over the onion and garlic mixture, stirring constantly for 1-2 minutes to cook the flour.
9. Whisk in Milk: Gradually add the milk, whisking continuously to prevent lumps and create a smooth sauce.
10. Simmer Sauce: Bring the sauce to a simmer over medium heat, then reduce heat to low and simmer for 5-7 minutes until thickened slightly.
11. Season Sauce: Stir in salt, pepper, and nutmeg. Adjust seasoning to taste.
12. Add Cheese to Sauce: Remove saucepan from heat and stir in 3/4 cup Gruyere, 3/4 cup cheddar, and 1/4 cup Parmesan until melted and creamy.
13. Combine Squash and 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 evenly.
15. Prepare Topping: In a small bowl, mix remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan, and panko breadcrumbs.
16. Sprinkle Topping: Evenly distribute the cheese and breadcrumb mixture over the top of the casserole.
17. Bake Au Gratin: Bake in the preheated oven for 20-25 minutes until the topping is golden brown and bubbly.
18. Rest the Dish: Remove from oven and let rest for 5-10 minutes before serving to set.
19. Garnish and Serve: Sprinkle chopped fresh parsley on top if desired, and serve hot for best flavor.

Notes

• Do not overcook the spaghetti squash to avoid mushy texture.
• Use high-quality cheeses for richest flavor.
• Adjust seasoning like salt and pepper to suit your taste preferences.
• This gratin can be assembled a day ahead and refrigerated; increase baking time by a few minutes if baking from cold.
• Add a pinch of red pepper flakes in the cheese sauce for a subtle kick.
• Experiment with different cheese varieties for unique flavor profiles.
• For a more filling meal, consider adding cooked bacon, ham, or sausage to the squash mixture.
• Ensure Parmesan is vegetarian-friendly, as some contain animal rennet.

Keywords: Spaghetti Squash, Au Gratin, Cheese Casserole, Vegetarian, Low Carb, Comfort Food, Gruyere, Cheddar, Parmesan, Roasted Squash