Name: Spaghetti Squash Au Gratin
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Yield: 4 servings
Cuisine: American
Ingredients: 1 medium spaghetti squash (about 2 pounds); 1 tablespoon olive oil; 1 small onion, finely chopped; 2 cloves garlic, minced; ½ cup shredded cheddar cheese; ½ cup shredded mozzarella cheese; ¼ cup grated Parmesan cheese; ½ cup panko breadcrumbs; 2 tablespoons unsalted butter, melted; ¼ teaspoon salt; ¼ teaspoon ground black pepper; ¼ teaspoon dried thyme

Hey y'all! If you’re searching for a dish that’s comforting, creamy, and downright delicious, you have to try Spaghetti Squash Au Gratin. This recipe takes the tender strands of spaghetti squash, bakes them in a cheesy, golden-brown casserole, and transforms a simple vegetable into something magical. Whether you need a cozy side, a satisfying meatless dinner, or just want to impress at your next potluck, this is the dish to make. Let's get cooking!

Why You'll Love This Spaghetti Squash Au Gratin

It’s packed with rich, cheesy flavor and a luscious creamy texture.
Lower in carbs and gluten-free—perfect for special diets.
Easy to prep and great for meal prepping ahead of time.
Pairs perfectly with almost any main course, from chicken to steak.
Keeps leftovers tasting just as good the next day!

Ingredients for Spaghetti Squash Au Gratin

1 large spaghetti squash (about 3 pounds)
2 tablespoons olive oil
1 small yellow onion, finely diced
2 cloves garlic, minced
¾ cup sour cream
½ cup grated Parmesan cheese
1 ½ cups shredded sharp cheddar cheese, divided
¼ teaspoon ground black pepper
½ teaspoon salt
⅛ teaspoon ground nutmeg (optional for a classic touch)
1 tablespoon chopped fresh parsley (for garnish)
Cooking spray

Directions: Step-by-Step Spaghetti Squash Au Gratin

Step 1: Prep and Roast the Spaghetti Squash

Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Slice the spaghetti squash in half lengthwise and scoop out the seeds. Drizzle with 1 tablespoon olive oil and season lightly with salt.
Place cut side down on the prepared sheet and roast for 35-40 minutes, until the flesh is tender and can be shredded into strands with a fork. Let cool for a few minutes.

Step 2: Prepare the Cheesy Mixture

While the squash roasts, heat 1 tablespoon olive oil in a skillet over medium heat. Add the onion and sauté until soft and translucent, about 5 minutes. Add garlic and cook for 1 minute.
In a large mixing bowl, combine cooked onion/garlic mixture, sour cream, Parmesan, 1 cup cheddar, black pepper, salt, and optional nutmeg.

Step 3: Assemble the Au Gratin Casserole

Using a fork, scrape the roasted spaghetti squash into strands. Add the squash to the cheese mixture and stir until well mixed.
Spray a 2-quart baking dish (see dish options) with cooking spray. Spread the squash mixture evenly inside. Top with remaining ½ cup cheddar.

Step 4: Bake Spaghetti Squash Au Gratin

Bake (uncovered) at 400°F (200°C) for 18-22 minutes, or until bubbling and the top is golden brown. Broil for 2-3 minutes for extra cheesy crispiness if desired.
Garnish with chopped parsley before serving. Enjoy hot!

Notes for Perfect Spaghetti Squash Au Gratin

Drain any liquid from the roasted squash to avoid a watery casserole.
For a deeper flavor, use a blend of sharp and smoked cheddar.
Learn more about proper cheese melting techniques from Serious Eats.