Healthy Spaghetti Squash Au Gratin

Healthy Spaghetti Squash Au Gratin is a cozy dish that gives you all the comfort of an old-school gratin without the heavy carbs. Roasted strands of spaghetti squash take the place of pasta or potatoes and get tossed with golden sautéed onions and garlic, creamy Greek yogurt, and plenty of sharp cheddar. The mixture bakes up warm and bubbly with a golden cheesy top that always disappears quickly at my table whether served as a centerpiece for meatless nights or a side for bigger holiday meals.

I first made this when I needed a lighter side dish for Thanksgiving and loved how satisfied everyone was. Even my most cheese-loving friends ask for the recipe all the time.

Ingredients

• Spaghetti squash: Choose one that feels heavy and has firm golden skin for best strands
• Olive oil: Brings out the squash’s naturally nutty flavor and helps it roast evenly
• Onion: Diced small to melt into the background and add rich sweetness
• Garlic: Fresh is best to bump up the savoriness
• Greek yogurt or sour cream: Makes it creamy without heaviness go for full-fat for extra flavor
• Sharp cheddar cheese: Freshly shredded melts best and provides the signature gratin tang
• Salt: Pick a fine sea salt for more even seasoning
• Black pepper: A fresh grind for a gentle kick
• Paprika or thyme: Totally optional but adds subtle warmth and color

Look for squash with a dry stem and no soft spots. Shred cheese from a block instead of pre-shredded for better results.

Step-by-Step Instructions

Prep and Roast the Squash:

Slice the spaghetti squash lengthwise with a large sharp knife and scoop out all the seeds with a spoon. Brush the cut sides with olive oil and lay them cut-side down on a lined baking sheet. Roast in the oven at 400°F for thirty five to forty minutes until a fork easily pierces the skin and the flesh pulls apart into strands

Sauté the Aromatics:

While the squash roasts heat a splash of olive oil in a skillet on medium heat. Add the diced onion and cook gently stirring often until the pieces turn soft and translucent after about five minutes. Stir in the minced garlic and cook for just one minute more making sure it does not burn. Remove the skillet from the heat

Shred and Mix:

When the roasted squash halves are cool enough to handle use a fork to gently pull the flesh into long noodle like strands. Place the strands in a large mixing bowl along with the sautéed onions and garlic. Add Greek yogurt one cup of shredded cheddar salt pepper and optional spices. Stir everything together until well combined

Assemble and Bake:

Grease a baking or casserole dish. Pour the squash mixture into the dish and spread it evenly. Sprinkle the remaining cheese over the top making sure it covers the whole surface. Bake at 375°F for twenty to twenty five minutes until the cheese is completely melted and golden brown

Cool and Serve:

Let the gratin cool for at least ten minutes so it sets up and is easier to serve. Scoop onto plates as a main or side and enjoy it warm

Save

I am always impressed by how much flavor the sharp cheddar brings. My kids love poking their forks into the crispy cheesy edge—the melted cheese on top is everybody’s favorite part and reminds me of Sunday dinners at my grandmother’s house.

Storage Tips

Let the gratin cool completely before covering the dish tightly and refrigerating. It will keep for up to three days. To reheat use a low oven or microwave until hot. If the top seems dry sprinkle a bit more cheese before warming up.

Ingredient Substitutions

If you run out of Greek yogurt swap in sour cream or even plain cottage cheese blended until smooth. A mix of mozzarella and parmesan also works instead of sharp cheddar for a milder flavor. Try adding spinach or cooked mushrooms to increase the veggie count or cooked chicken for protein.

Serving Suggestions

This dish is delicious on its own but pairs well with roasted chicken grilled sausages or a green salad. For potlucks transfer to a slow cooker to keep it warm. As a light main dish I sometimes serve it with crusty bread and a simple tomato salad.

Cultural Context

Au gratin traditionally means a crispy browned top and usually involves potatoes or pasta. Using spaghetti squash updates this classic French comfort dish for today’s lighter tastes. It is a favorite in my kitchen during chilly months when I crave hearty meals without feeling weighed down.

Recipe FAQs

→ How do I prepare spaghetti squash for this dish?

Slice the squash in half lengthwise, scoop out seeds, brush with olive oil, and roast cut-side down until tender. Once cool, use a fork to shred into strands.

→ Can I use sour cream instead of Greek yogurt?

Yes, sour cream can be used for a richer flavor and creamier consistency. Either works well in the mixture.

→ How can I make the topping crispier?

For extra crunch, sprinkle almond flour or crushed pork rinds over the cheese before baking. This adds texture and flavor.

→ Is this dish suitable for a low-carb diet?

Absolutely—spaghetti squash is naturally low-carb, and the dish is packed with veggies and lean dairy for a lighter meal.

→ What proteins can I add for a heartier meal?

Stir in cooked chicken, bacon, or mushrooms with the squash mixture before baking for extra protein and flavor.

→ How well do leftovers keep?

Leftovers stay fresh and delicious—refrigerate and reheat gently before enjoying. Flavors often deepen overnight.