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Baked Spaghetti Squash Gratin topped with cheese and herbs

Spaghetti Squash Gratin

A lighter alternative to classic potatoes au gratin, this dish combines roasted spaghetti squash with a creamy béchamel sauce and a crispy cheese topping.
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Prep Time 20 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 35 minutes
Servings: 6 servings
Course: Main Course, Side Dish
Cuisine: American
Calories: 360
Ingredients Method Notes

Ingredients
  

For the Gratin
  • 1 large spaghetti squash (about 3-4 pounds)
  • 4 tablespoons unsalted butter, divided 2 tablespoons for roasting, 2 tablespoons for the roux
  • 1 medium yellow onion, finely chopped
  • 2 cloves garlic, minced
  • 4 tablespoons all-purpose flour
  • 3 cups whole milk Use for richness
  • 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 Reserve some for topping
  • 1 cup grated sharp cheddar cheese, divided Reserve some for topping
  • 1/2 cup grated Parmesan cheese, divided Reserve some for topping
  • 1/4 cup panko breadcrumbs For crispy topping
  • 2 tablespoons chopped fresh parsley, for garnish (optional)

Method
 

Preparation
  1. Preheat oven to 400 F (200 C).
  2. Cut the spaghetti squash in half lengthwise, scoop out the seeds, drizzle with 2 tablespoons melted butter and season with salt and pepper.
  3. Place cut-side down on a baking sheet and roast for 45-60 minutes until tender.
  4. Once cool, shred the spaghetti squash with a fork.
Making the Sauce
  1. In a saucepan, melt the remaining butter over medium heat, sauté onion until softened, then add garlic and cook for 1 more minute.
  2. Sprinkle flour over the onion and garlic, cook to form a roux.
  3. Gradually whisk in the milk until smooth; bring to a simmer, stirring constantly for 5-7 minutes until thickened.
  4. Stir in salt, pepper, nutmeg, and 3/4 cup each of Gruyere and cheddar cheese until melted.
Assembling the Gratin
  1. Combine the shredded squash with the cheese sauce.
  2. Transfer to a greased 9x13 inch baking dish.
  3. In a bowl, mix remaining cheeses and panko for topping, sprinkle over the squash mixture.
Baking
  1. Bake for 20-25 minutes until golden brown and bubbly.
  2. Let rest for 5-10 minutes; garnish with parsley and serve hot.

Notes

Serve with a crisp green salad and consider a light-spiced apple dessert like applesauce cake for dessert. For storage, cool completely, cover tightly, and refrigerate for up to 3-4 days. Reheat in a 350 F oven until warmed through, about 15-20 minutes.