Spaghetti Squash Au Gratin

Spaghetti squash au gratin transforms the humble squash into a decadent, cheese-filled delight that satisfies comfort food cravings without the carb overload. This innovative dish brilliantly replaces traditional potatoes with tender strands of spaghetti squash, creating a creamy, cheesy experience that's incredibly satisfying while being surprisingly low in carbohydrates. Whether served as a hearty side dish or a complete meal with the addition of chicken, this versatile recipe delivers rich flavor and creamy texture that will convince even dedicated potato lovers to make the switch to this healthier alternative.

I discovered this recipe while searching for creative, low-carb alternatives to my favorite comfort foods. The first time I served it to my family, they couldn't believe how satisfying and delicious it was despite having no potatoes! It's now a regular in our dinner rotation - sometimes with chicken as a main dish, other times without as a side for holiday meals or Sunday dinners.

Ingredients and Selection Tips

• Spaghetti Squash: Choose one that feels heavy for its size with firm, unblemished skin; a 3-4 pound squash works perfectly
• Chicken Breast: Optional but adds protein for a complete meal; boneless, skinless works best
• Greek Yogurt: Creates creaminess with added protein; sour cream can substitute for a richer result
• Cheddar Cheese: Sharp varieties provide the most flavor; freshly grated melts better than pre-packaged
• Onion: Sautéed until very soft for sweet, caramelized flavor throughout the dish
• Butter: Adds richness when cooking the onions; use unsalted to control saltiness

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Detailed Cooking Instructions

Step 1:

Begin by preheating your oven to 375°F (190°C) and lining a rimmed baking sheet with aluminum foil for easy cleanup. This preliminary step ensures your oven is properly heated when you're ready to roast the squash and chicken.

Step 2:

Carefully cut one medium spaghetti squash (about 3-4 pounds) in half lengthwise using a sharp knife. The tough exterior requires some strength, so work slowly and carefully. Once halved, use a spoon to scrape out all the seeds and stringy pulp from the center cavity, creating a clean hollow in each half.

Step 3:

Drizzle the cut sides of the squash with about 1 tablespoon of olive oil, then season generously with ½ teaspoon of salt and ¼ teaspoon of black pepper, distributing the seasonings evenly over both halves. This initial seasoning infuses flavor directly into the squash as it roasts.

Step 4:

Place the squash halves cut-side down on your prepared baking sheet, which allows them to steam and roast simultaneously for the perfect tender texture. If including chicken, place 1 pound of boneless, skinless chicken breast (cut into 4 equal pieces) on the same baking sheet and season with salt and pepper.

Step 5:

Roast the squash and chicken together for approximately 45 minutes, until the squash flesh is tender enough to easily pierce with a fork and the chicken reaches an internal temperature of 165°F (74°C). Cooking times may vary slightly depending on the size of your squash and chicken pieces.

Step 6:

While the squash and chicken are roasting, finely dice one medium onion and sauté it in 2 tablespoons of butter over medium-low heat. Allow the onions to cook slowly for about 15-20 minutes until they become very soft and translucent with slight caramelization. Add 2 minced garlic cloves during the final 2 minutes of cooking.

Step 7:

Once the squash is cool enough to handle, use a fork to gently scrape the flesh, creating spaghetti-like strands. Start from the edges and work toward the center, being careful not to pierce through the skin if you plan to use the shells as serving vessels. Transfer the squash strands to a large mixing bowl.

Step 8:

Dice the cooked chicken into small, bite-sized pieces approximately ½-inch in size, ensuring even distribution throughout the dish. Add the chicken to the bowl with the spaghetti squash strands.

Step 9:

To the squash and chicken, add the sautéed onions and garlic, ¾ cup of Greek yogurt (or sour cream), 1 cup of shredded cheddar cheese, ½ teaspoon of salt, and ¼ teaspoon of black pepper. Gently fold all ingredients together until thoroughly combined, being careful not to mash the squash strands.

Step 10:

Spoon the mixture back into the empty squash shells, or transfer to a greased 2-quart baking dish if preferred. Top with an additional ½ cup of shredded cheddar cheese, and place under the broiler for 3-5 minutes, watching carefully until the cheese is melted and golden brown with some crispy edges.

I learned these tips through my own experimentation with this recipe. The first time I made it, I overcooked the squash and ended up with more of a mash than those lovely spaghetti strands. Now I check it frequently during roasting, looking for tender but still structured flesh.

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The first time I served this at a holiday gathering, my skeptical potato-loving relatives were dubious about a squash replacement for their beloved au gratin. After the first bite, their doubts vanished! What makes this recipe truly special is how it manages to deliver all the creamy, cheesy satisfaction of traditional potato gratin while being significantly lighter and lower in carbs. The natural mild sweetness of the spaghetti squash pairs beautifully with the sharp cheddar and savory onions, creating a complex flavor profile that actually surpasses its potato-based inspiration. Whether you're following a specific eating plan or simply looking to incorporate more vegetables into your meals, this spaghetti squash au gratin proves that healthy alternatives can be even more delicious than the originals.

Frequently Asked Questions

→ Can I make this recipe vegetarian?

Absolutely! Simply omit the chicken and add more vegetables like sautéed mushrooms, bell peppers, or zucchini for bulk and flavor. You could also add a can of rinsed and drained white beans or chickpeas for added protein.

→ How do I know when my spaghetti squash is fully cooked?

A properly cooked spaghetti squash should be tender enough that you can easily pierce it with a fork, but not so soft that it becomes mushy. When you scrape the flesh with a fork, it should separate easily into spaghetti-like strands.

→ Can I prepare this dish ahead of time?

Yes! You can prepare all components ahead of time and store them separately in the refrigerator for 1-2 days. Alternatively, you can assemble the entire dish, cover, and refrigerate for up to 24 hours before baking. If baking from refrigerated, add 10-15 minutes to the final baking time.

→ What other cheeses work well in this recipe?

While cheddar is specified in the recipe, other great options include Gruyère for a nutty flavor, Monterey Jack for a mild, melty texture, or a blend of Parmesan and mozzarella. For a more complex flavor profile, consider using a combination of cheeses.

→ Is this recipe keto-friendly?

Yes, this recipe is suitable for a ketogenic diet, especially if you use sour cream instead of Greek yogurt as mentioned in the notes. Spaghetti squash is low in carbs but high in fiber, making it an excellent pasta alternative for those following keto or other low-carb eating plans.