Ingredients:

  • 1 large spaghetti squash (about 3 lbs), halved and seeded
  • 1 Tbsp olive oil
  • 4 Tbsp unsalted butter
  • 1/2 cup finely diced yellow onion
  • 2 cloves garlic, minced
  • 3 Tbsp all-purpose flour
  • 2 cups whole milk (or half-and-half), warmed slightly
  • 1/2 cup low sodium chicken or vegetable broth
  • 1 tsp dry Dijon mustard
  • 1 tsp smoked paprika
  • 1/2 tsp fresh thyme leaves (or 1/4 tsp dried)
  • 1 cup shredded sharp Cheddar cheese
  • 1 cup shredded Gruyère cheese, divided
  • 2 Tbsp chopped fresh parsley
  • 1/2 cup Panko breadcrumbs
  • Salt and freshly ground black pepper, to taste

Instructions:

  1. Preheat oven to 400°F (200°C). Halve the spaghetti squash, drizzle with olive oil, season generously with salt and pepper. Place cut-side down on a baking sheet and roast until fork-tender, about 45-60 minutes.
  2. Once cool enough to handle, use a fork to scrape out the strands of squash and place them in a large bowl. Discard the seeds and skin.
  3. Melt butter in a large skillet or Dutch oven over medium heat. Sauté the diced onion until soft, about 5 minutes. Add minced garlic and cook for 1 minute more until fragrant.
  4. Whisk in the flour to the butter/onion mixture, cooking for 1 minute to cook out the raw flour taste (creating a roux).
  5. Gradually whisk in the warm milk and broth until the mixture is smooth. Bring to a gentle simmer, whisking constantly, until the sauce thickens enough to coat the back of a spoon.
  6. Remove the sauce from the heat. Stir in Dijon mustard, smoked paprika, thyme, salt, and pepper. Stir in the sharp Cheddar and half (1/2 cup) of the Gruyère until completely melted and smooth. Mix in the fresh parsley.
  7. Pour the cheese sauce over the shredded spaghetti squash in the bowl. Mix gently but thoroughly until every strand is coated evenly.
  8. Transfer the squash mixture into a lightly greased 9x13 inch baking dish. In a small bowl, combine the remaining 1/2 cup Gruyère with the Panko breadcrumbs. Sprinkle this topping evenly over the casserole.
  9. Bake for 20-25 minutes, or until the edges are bubbly and the topping is golden brown and crisp. Let rest for 10 minutes before serving.