If you’re hunting for a comforting, cozy dish that still feels fresh and healthy, you’re going to adore this Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe. I absolutely love how the tender spaghetti squash strands soak up a luscious creamy Gruyère sauce, all while the savory turkey and caramelized onions add layers of flavor. It’s one of those dishes that feels like a warm hug on a plate, perfect for chilly evenings or whenever you want something satisfying without the heaviness of pasta.
When I first tried this recipe, the crispy French fried onions on top totally won me over—they add this unexpected crunch that you’ll find makes every bite delightful. It’s also a wonderful way to sneak in veggies like spinach and herbs, making it feel wholesome yet indulgent. Trust me, this Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe is worth keeping in your regular dinner rotation!
Why You’ll Love This Recipe
- Comfort meets healthy: You get a creamy, cheesy casserole that uses spaghetti squash instead of pasta for a lighter feel.
- Flavor-packed layers: The turkey, Gruyère, and crispy onions combine to create a complex, savory profile that keeps you coming back for more.
- Family-friendly: My whole family goes crazy for this dish—it’s a great way to please kids and adults alike without extra fuss.
- Make-ahead friendly: You can prep parts ahead and just pop it in the oven when you’re ready, perfect for busy weeknights or guests.
Ingredients You’ll Need
These ingredients work beautifully together to create a rich, flavorful casserole that balances protein, veggies, and that gorgeous melted cheese. Shopping for fresh herbs and good quality Gruyère really pays off here—trust me, it makes a noticeable difference!
- Spaghetti Squash: The star swap for pasta, it roasts into tender strands that soak up sauce like a dream.
- Ground Turkey: Lean and mild, it pairs perfectly with bold Gruyère and savory herbs.
- Gruyère Cheese: Melts into a creamy, nutty sauce that adds sophistication with every bite.
- French Fried Onions: These crispy onions add the best crunch topping—don’t skip them!
- Baby Spinach: Adds a fresh pop of green and a mild flavor that blends well with turkey.
- Fresh Sage and Thyme: These herbs elevate the casserole with their subtle earthiness and aroma.
- Garlic and Onion (fresh and granulated): Build the savory base and deepen the flavor complexity.
- Butter, Flour, and Milk: For the creamy Gruyère sauce—think of it as your comforting cheesy blanket.
- Olive Oil: Used to roast the squash and sauté, bringing richness and flavor.
- Salt, Black Pepper, White Pepper, Italian Seasoning, Nutmeg: Essential seasonings that balance and brighten the dish.
Variations
I love mixing things up with this recipe depending on what I have on hand or the season. Don’t hesitate to make it your own—the base is versatile and welcoming!
- Cheese Swap: Try substituting Gruyère with sharp cheddar or fontina for a different cheesy vibe—I’ve done both, and they’re equally delicious.
- Meat Options: Ground chicken, pork, or even leftover roast beef work well if ground turkey isn’t your favorite or you want variety.
- Veggie Boost: Feel free to toss in mushrooms or roasted red peppers with the spinach to up the veggie content.
- Make It Vegetarian: Skip the turkey and add extra spinach and mushrooms with a bit of smoked paprika to maintain richness.
How to Make Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe
Step 1: Roast Your Spaghetti Squash to Perfection
Start by preheating your oven to 400°F and lining a baking sheet with foil—makes cleanup a breeze. Drizzle olive oil over the cut sides of your halved spaghetti squash, season generously with salt, pepper, granulated onion, and garlic. Place the squash cut-side down on your prepared baking sheet and roast for about an hour. You’ll know it’s ready when a skewer slides in easily and the flesh feels tender. Be patient here: the longer roast softens the squash into strands that hold up well in the casserole.
Step 2: Sauté Onions and Brown Ground Turkey
While your squash is roasting, get a large skillet hot over medium-high heat with a good drizzle of olive oil. Toss in your sliced onions with a pinch of salt and pepper, stirring occasionally until they’re golden brown and sweet—about 10 minutes. Then add ground turkey, season with salt, pepper, and white pepper, and break it apart with your spatula. Cook the mixture until the turkey turns a deep golden hue—this step seals in flavor and keeps the meat juicy. Toss in pressed garlic and spinach, letting the spinach wilt quickly, then stir in the fresh sage and thyme. Remove from heat and set aside—try not to sneak bites!
Step 3: Fluff Your Spaghetti Squash and Prep the Sauce
Once your squash is cool enough to handle (about 20 minutes), grab a fork and gently scrape the flesh into a big bowl—it should separate nicely into spaghetti-like strands. Next, it’s time for that dreamy creamy Gruyère sauce. In a pot over medium heat, melt butter with garlic, then whisk in flour to make a roux. Slowly whisk in milk, making sure to keep it lump-free, and let it simmer until thick and creamy. Turn off heat and season with salt, pepper, Italian seasoning, and a little nutmeg for warmth. Stir in grated Gruyère until melted and silky—this sauce is pure comforting magic!
Step 4: Assemble and Bake Your Casserole
Combine the spaghetti squash strands with the turkey and spinach mixture, then gently fold in the Gruyère sauce—don’t overmix, but make sure everything is cozy and combined. Lightly spray a 3-quart baking dish and transfer the mixture inside. Top with a generous layer of grated Gruyère cheese, then bake uncovered at 375°F for 20 minutes to get bubbly and golden. Finally, sprinkle the crispy French fried onions on top and bake for another 5 minutes for that irresistible crunch. Let the thyme leaves go on as garnish right before serving to brighten up each portion.
Pro Tips for Making Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe
- Don’t Overcook the Squash: Roast until tender but not mushy, so the strands hold texture and don’t turn to mush when mixed with sauce.
- Use Fresh Herbs: I learned fresh sage and thyme make a huge difference—skip dried here if you can for the best flavor boost.
- Make the Sauce Slowly: Whisk gradually when adding milk to avoid lumps and ensure a smooth, velvety Gruyère sauce.
- Add Onions Last: Wait to top with crispy fried onions until the very end to keep them crunchy instead of soggy.
How to Serve Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe
Garnishes
I usually sprinkle fresh thyme leaves right on top before serving—they add a lovely, fresh aroma and a pop of color that makes the casserole look as good as it tastes. A small drizzle of good olive oil or a pinch of freshly cracked black pepper never hurts either, especially if you want to add a little flair at the table.
Side Dishes
This casserole acts as a full meal, but if you want to round things out, I like serving it with a crisp mixed green salad or some roasted seasonal veggies like Brussels sprouts or asparagus. Garlic bread or a simple herb focaccia can also work if you want a bit of indulgence on the side.
Creative Ways to Present
For holidays or special dinners, I love making individual portions in small ramekins topped with extra crispy onions and a sprig of thyme—super charming and perfect for sharing. This also makes it easy to prep ahead and bake just before serving.
Make Ahead and Storage
Storing Leftovers
I keep leftovers covered tightly in an airtight container in the fridge for up to 3 days. The casserole tastes even better after the flavors have had time to meld together overnight, though the crispy onions lose their crunch and might need to be freshened up before serving again.
Freezing
This casserole freezes beautifully! Just assemble and bake as instructed, then cool completely before wrapping tightly and freezing. When you’re ready, thaw overnight in the fridge and reheat in the oven for best results. I’ve found freezing slightly softens the onions, so you might want to add fresh crispy onions on top after reheating.
Reheating
Reheat leftovers gently in a 350°F oven, covered loosely with foil to prevent drying out, for about 15-20 minutes or until warmed through. If you want to restore crunch, add fresh French fried onions in the last 5 minutes of reheating—they bring that delightful texture back perfectly.
FAQs
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Can I use a different type of squash for this casserole?
While spaghetti squash is ideal for mimicking pasta strands, you can experiment with other squash like butternut or acorn. Just keep in mind they have a different texture and won’t create the same noodle-like strands, so the overall dish might feel a bit denser or chunkier.
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Is there a way to make this recipe dairy-free?
Absolutely! You can swap the Gruyère cheese with a dairy-free melty cheese alternative and use plant-based milk for the creamy sauce. Keep in mind the flavor profile will change, so adding nutritional yeast or smoked paprika might help boost the savory depth.
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How do I know when the spaghetti squash is fully cooked?
Roast until you can easily pierce the squash with a skewer or fork and the flesh feels tender when gently pressed. Usually around 1 hour at 400°F, but size may vary, so check for softness rather than strictly timing it.
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Can I prepare this dish completely ahead of time?
Yes! You can prepare all components up to mixing and assembling the casserole, then cover and refrigerate it for up to 24 hours before baking. Just add the crispy onions on top right before baking or shortly before serving to keep them crunchy.
Final Thoughts
This Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe is one of those dishes I keep coming back to because it manages to be cozy, flavorful, and just a little bit special all at once. It’s perfect when you want something that satisfies a comfort food craving but keeps things on the lighter side. I hope you’ll give it a try soon—you’ll love how simple ingredients come together to create such a memorable meal your family won’t stop asking for!
Print
Spaghetti Squash Casserole with Turkey, Gruyère, and Crispy Onions Recipe
- Prep Time: 25 minutes
- Cook Time: 1 hour 20 minutes
- Total Time: 1 hour 45 minutes
- Yield: Serves 8
- Category: Casserole
- Method: Baking
- Cuisine: American
Description
This Spaghetti Squash Casserole is a comforting, cheesy, and wholesome dish featuring roasted spaghetti squash strands combined with a savory ground turkey, onion, and spinach mixture, all enveloped in a creamy Gruyere sauce. Topped with crispy French fried onions and freshly chopped herbs, this casserole brings a delightful texture and an elegant flavor to your dinner table, perfect for a nutritious family meal.
Ingredients
Casserole Ingredients:
- 2 (roughly 3 pound) spaghetti squash, halved and seeds discarded
- Olive oil (for drizzling and sautéing)
- Salt (to taste)
- Black pepper (to taste)
- 1/2 teaspoon granulated onion
- 1/2 teaspoon granulated garlic
- 1 medium onion, quartered and thinly sliced
- 1/2 pound ground turkey
- 1/4 teaspoon white pepper
- 4 cloves garlic, pressed through garlic press
- 2 cups (packed) baby spinach leaves
- 1 1/2 tablespoon chopped fresh sage leaves
- 1 teaspoon fresh thyme leaves, plus extra for garnish
- 3/4 cup grated Gruyere cheese
- 1/2 cup crispy French fried onions
Creamy Gruyere Sauce Ingredients:
- 3 tablespoons unsalted butter
- 2 cloves garlic, pressed through garlic press
- 5 tablespoons (level) flour (roughly 1 1/2 ounces)
- 3 cups whole milk
- Salt (to taste)
- Black pepper (to taste)
- 1 teaspoon Italian seasoning
- Pinch nutmeg
- 1/4 cup grated Gruyere cheese
Instructions
- Prepare Spaghetti Squash: Preheat the oven to 400°F and line a large baking sheet with foil. Drizzle olive oil over the cut sides of the spaghetti squash halves, then sprinkle with salt, black pepper, granulated onion, and granulated garlic. Place the squash halves cut-side down on the baking sheet and roast for about 1 hour or until tender and easily pierced with a skewer.
- Sauté Onions and Cook Turkey: While the squash roasts, heat 3 tablespoons of olive oil in a large heavy-bottom skillet over medium-high heat. Add the sliced onions with salt and pepper and sauté for about 10 minutes until golden brown. Add the ground turkey along with white pepper, salt, and black pepper. Break it up finely and cook until the turkey turns a deep golden brown, about 2-3 minutes.
- Add Garlic, Spinach, and Herbs: Stir the pressed garlic into the turkey mixture, then add the baby spinach and cook until wilted, about 30 seconds to 1 minute. Stir in the chopped fresh sage and fresh thyme leaves. Remove the mixture from the skillet and set aside in a bowl.
- Cool and Shred Squash: Remove the roasted spaghetti squash from the oven and allow to cool for 20 minutes until it can be handled. Reduce the oven temperature to 375°F. Using a fork, pull the flesh away from the shell to create spaghetti-like strands and place them in a large bowl.
- Make Creamy Gruyere Sauce: In a medium-large pot over medium heat, melt the butter with pressed garlic. Sprinkle in the flour and whisk to form a roux. Gradually whisk in the milk, stirring constantly to prevent lumps. Bring the sauce to a vigorous simmer and allow it to thicken, simmering for an additional 2-3 minutes to tighten the sauce.
- Season and Add Cheese: Remove the sauce from heat and season with salt, black pepper, Italian seasoning, and a pinch of nutmeg. Taste and adjust seasoning as needed. Stir in ¼ cup grated Gruyere cheese until fully melted and blended.
- Combine and Assemble Casserole: Add the shredded spaghetti squash strands and the turkey/onion/spinach mixture into the Gruyere sauce. Gently mix everything together, ensuring even coating and flavor. Season with additional salt or pepper as desired.
- Prepare Baking Dish: Lightly mist a 3-quart baking dish with cooking spray. Spoon the combined casserole mixture into the dish and sprinkle ¾ cup grated Gruyere cheese evenly over the top.
- Bake Casserole: Bake the casserole in the preheated 375°F oven uncovered for 20 minutes. After 20 minutes, sprinkle the top with ½ cup crispy French fried onions and bake for an additional 5 minutes until the topping is golden and crispy.
- Garnish and Serve: Remove from the oven and garnish with fresh thyme leaves before serving warm. Enjoy your cheesy, comforting spaghetti squash casserole!
Notes
- Roasting the spaghetti squash cut-side down helps it cook evenly and retain moisture.
- You can substitute ground turkey with ground chicken or lean ground beef if preferred.
- Gruyere cheese adds a rich and nutty flavor; Swiss cheese can be used as a milder alternative.
- If you want a vegetarian version, omit the ground turkey and substitute with mushrooms or a plant-based meat alternative.
- Make sure to fully simmer the sauce to avoid a raw flour taste and ensure a creamy texture.
- French fried onions add a delightful crunch on top, but you can use breadcrumbs or toasted panko as a substitute.
