Cheesy Baked Spaghetti Squash Au Gratin Recipe

Introduction

This creamy spaghetti squash au gratin is a comforting and flavorful dish that transforms healthy squash into a cheesy, satisfying meal. With a golden, bubbly topping and a rich cheese sauce, it’s perfect for a cozy dinner or a family gathering.

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 oven to 400°F (200°C).
2. Step 2: Cut the spaghetti squash in half lengthwise. Scoop out the seeds and stringy bits.
3. Step 3: Drizzle the cut sides of the squash with 2 tablespoons of melted butter. Sprinkle generously with salt and pepper.
4. Step 4: Place the squash halves cut-side down on a baking sheet lined with parchment paper. Roast for 45-60 minutes, or until the squash is tender and easily pierced with a fork.
5. Step 5: Once cool enough to handle, use a fork to shred the flesh into spaghetti-like strands. Set aside.
6. Step 6: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter.
7. Step 7: Add the chopped onion to the melted butter and cook until softened and translucent, about 5-7 minutes. Add the minced garlic and cook for another minute, until fragrant.
8. Step 8: Sprinkle the flour over the onion and garlic mixture. Cook, stirring constantly, for 1-2 minutes to create a roux.
9. Step 9: Gradually whisk in the milk, a little at a time, ensuring there are no lumps. Continue whisking until the sauce is smooth.
10. Step 10: Bring the sauce to a simmer over medium heat, stirring constantly. Reduce heat to low and simmer for 5-7 minutes until the sauce thickens slightly.
11. Step 11: Stir in salt, pepper, and nutmeg. Taste and adjust seasoning as needed.
12. Step 12: Remove from heat. Stir in 3/4 cup Gruyere, 3/4 cup cheddar, and 1/4 cup Parmesan until melted and smooth. Reserve remaining cheese for topping.
13. Step 13: Add the shredded spaghetti squash to the cheese sauce and gently stir to combine.
14. Step 14: Pour the mixture into a greased 9×13 inch baking dish.
15. Step 15: In a small bowl, combine the remaining 1/4 cup Gruyere, 1/4 cup cheddar, 1/4 cup Parmesan, and panko breadcrumbs.
16. Step 16: Sprinkle the cheese and breadcrumb mixture evenly over the squash.
17. Step 17: Bake for 20-25 minutes, until the topping is golden brown and bubbly.
18. Step 18: Remove from oven and let rest for 5-10 minutes before serving.
19. Step 19: Garnish with chopped fresh parsley if desired. Serve hot and enjoy!

Tips & Variations

• Use a mix of your favorite cheeses for different flavor profiles or add a pinch of cayenne for a subtle kick.
• For a vegetarian version, ensure the cheese and butter used have no animal rennet.
• Try adding cooked mushrooms or spinach to the cheese sauce for extra veggies.
• If you prefer, swap panko breadcrumbs for crushed crackers or omit for a gluten-free topping.

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, or microwave in short intervals to avoid drying out. This dish is best enjoyed fresh but holds up well when reheated.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I use regular pasta instead of spaghetti squash?

Yes, you can substitute cooked spaghetti or any pasta of your choice, but the dish will no longer be low-carb or gluten-free. The sauce and topping work equally well with regular pasta.

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

The squash is ready when the flesh is tender and easily pierced with a fork. It should pull apart into strands without resistance and be soft to the touch.

Cheesy Baked Spaghetti Squash Au Gratin Recipe

Print Recipe

★★★★★

4.5 from 71 reviews

This creamy and cheesy Spaghetti Squash Au Gratin is a comforting vegetarian dish that combines roasted spaghetti squash strands with a rich three-cheese sauce, then topped with a golden breadcrumb crust. It’s an elegant, low-carb alternative to traditional pasta dishes, baked to bubbly perfection with Gruyere, cheddar, and Parmesan cheeses.

• Author: Caleb
• Prep Time: 15 minutes
• Cook Time: 1 hour 10 minutes
• Total Time: 1 hour 25 minutes
• Yield: 6 servings 1x
• Category: Main Course
• Method: Baking
• Cuisine: American
• Diet: Vegetarian

Ingredients

Scale 1x2x3x

Spaghetti Squash

• 1 large spaghetti squash (about 3–4 pounds)
• 2 tablespoons unsalted butter, melted (for squash)
• 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
• 1/4 teaspoon black pepper
• 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 the oven: Set your oven to 400°F (200°C) to prepare for roasting the spaghetti squash.
2. Prepare the squash: Cut the spaghetti squash lengthwise in half and scoop out the seeds and stringy bits from the center.
3. Season the squash: Drizzle the cut sides of the squash with 2 tablespoons of melted butter, then sprinkle generously with salt and black pepper for flavor.
4. Roast the squash: Place the squash halves cut-side down on a parchment-lined baking sheet and roast in the oven for 45-60 minutes until the flesh is tender and easily pierced with a fork.
5. Shred the spaghetti squash: Once cool enough to handle, use a fork to scrape out the flesh into long, spaghetti-like strands; set aside.
6. Melt butter for sauce: In a large saucepan over medium heat, melt the remaining 2 tablespoons of butter to prepare for making the cheese sauce.
7. Sauté onion and garlic: Add the finely chopped onion to the melted butter and cook for 5-7 minutes until softened and translucent. Add minced garlic and cook for an additional minute until fragrant.
8. Make a roux: Sprinkle the flour over the onion and garlic mixture and stir constantly for 1-2 minutes to cook out the raw flour taste and form a roux.
9. Whisk in milk: Gradually add the whole milk a little at a time while whisking constantly to avoid lumps. Continue whisking until the sauce is smooth.
10. Simmer the sauce: Bring the sauce to a gentle simmer over medium heat, stirring constantly. Reduce the heat and let it simmer for 5-7 minutes until it thickens slightly.
11. Season the sauce: Stir in salt, black pepper, and nutmeg. Taste and adjust seasonings as needed to balance 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 cheese until melted and the sauce is creamy and smooth. Reserve the remaining cheese for topping.
13. Combine squash and sauce: Gently fold the shredded spaghetti squash 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, and panko breadcrumbs to create the crispy topping.
16. Sprinkle the topping: Evenly distribute 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 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 before serving.
19. Garnish and serve: Optionally sprinkle chopped fresh parsley over the top for a pop of color and freshness. Serve hot and enjoy!

Notes

• Be sure not to overcook the squash, as it should shred easily but not become mushy.
• The sauce can be prepared ahead and refrigerated; reheat gently before combining with the squash.
• If you prefer a dairy-free version, substitute butter and milk with plant-based alternatives and use vegan cheeses.
• Panko breadcrumbs add a nice crunchy texture, but you can omit if gluten-free is desired.
• Leftovers can be stored in the refrigerator for 3-4 days and reheated in the oven to maintain crispiness.

Keywords: spaghetti squash, au gratin, cheesy casserole, vegetarian, low carb, baked squash, Gruyere cheese, cheddar cheese, Parmesan, comfort food