Cheesy Butternut Squash Casserole is the perfect cozy dish that blends sweet, tender squash with gooey, melted cheese for a comforting treat. The combination of soft butternut squash and the rich, cheesy topping makes every bite warm and satisfying. It’s easy to put together and feels special enough to serve for family dinners or holiday gatherings.
I love making this casserole when the weather turns cool because it fills the kitchen with a lovely, inviting aroma. A little tip I always keep in mind is to roast the squash just right so it stays soft but still holds its shape in the casserole. That way, you get those tender bites mixed with the creamy cheese that everyone ends up loving.
One of my favorite ways to serve this dish is as a side alongside roasted chicken or turkey. It’s also great on its own when you want something simple but tasty. I often find myself going back for seconds because the flavors are just so comforting and familiar, like a warm hug on a plate.
Key Ingredients & Substitutions
- Butternut Squash
- This is the star of the dish. Choose a firm, unblemished squash for a sweeter flavor. You can swap it with other winter squashes like acorn or kabocha if needed, but the texture will vary slightly.
- Italian Sausage
- Optional but adds a nice savory depth. For a vegetarian option, replace with sautéed mushrooms or a plant-based sausage. Make sure to remove casings before cooking if using regular sausage.
- Cheese
- Mozzarella and Parmesan melt beautifully here. If you can’t find these, try cheddar for a sharper taste or Monterey Jack for milder meltiness. The key is using good melting cheeses.
- Herbs (Sage & Thyme)
- These bring out the earthy flavor in the squash. Fresh herbs are best but dried works well too. Feel free to experiment with rosemary or oregano for a twist.
How Do You Get the Butternut Squash Tender But Not Mushy?
Roasting the squash before adding it to the casserole ensures it’s perfectly tender without getting soggy in the dish. Here’s how:
- Peel and cube the squash into even 1-inch pieces for uniform cooking.
- Toss with olive oil, salt, and pepper to boost flavor and promote roasting.
- Spread in a single layer on a baking sheet to avoid steaming.
- Roast at 375°F (190°C) for 25-30 minutes, stirring halfway to brown evenly.
This method locks in a slight firmness while softening the inside, making the squash hold up well in the casserole without turning mushy.
Equipment You’ll Need
- Medium baking sheet – perfect for roasting butternut squash evenly without crowding.
- Large skillet – lets you sauté onions, cook sausage, and mix ingredients all in one pan.
- Casserole dish (8×8-inch or similar) – holds the squash mixture and cheese for baking nicely.
- Sharp knife and cutting board – essential for peeling and cubing the butternut squash safely.
- Mixing spoon or spatula – helps you gently combine ingredients without breaking the squash.
Flavor Variations & Add-Ins
- Swap Italian sausage for cooked bacon or pancetta for smoky richness.
- Add cooked quinoa or wild rice to make the casserole heartier and add texture.
- Mix in chopped kale or spinach for a boost of green and mild bitterness.
- Use sharp cheddar instead of mozzarella for a tangier, bolder cheese flavor.
Cheesy Butternut Squash Casserole
Ingredients You’ll Need:
Main Ingredients:
- 1 medium butternut squash (about 3 cups peeled and cubed)
- 1 tablespoon olive oil
- 1 small onion, chopped
- 2 cloves garlic, minced
- 1/2 pound Italian sausage (optional), casings removed
- 1/2 cup red bell pepper, diced
- 1 teaspoon dried sage (or 1 tablespoon fresh sage, chopped)
- 1 teaspoon dried thyme
- Salt and pepper, to taste
- 1 cup shredded mozzarella cheese
- 1/2 cup grated Parmesan cheese
- 1/2 cup heavy cream (or half-and-half)
- 2 tablespoons fresh parsley, chopped (for garnish)
- 1 tablespoon butter (optional, for sautéing)
How Much Time Will You Need?
This casserole takes about 15 minutes of prep time, 25-30 minutes to roast the squash, plus 15-20 minutes baking time. In total, plan for roughly 1 hour from start to serving.
Step-by-Step Instructions:
1. Prepare the Oven and Squash:
Preheat your oven to 375°F (190°C). Grease a medium casserole dish and set aside. Peel the butternut squash and cut it into 1-inch cubes. Toss the cubes with olive oil, salt, and pepper, then spread them out on a baking sheet.
2. Roast the Squash:
Roast the squash in the oven for 25-30 minutes until tender but still holding their shape. Stir the cubes halfway through to ensure even cooking.
3. Cook the Sausage and Vegetables:
While the squash roasts, heat olive oil and butter (if using) in a large skillet over medium heat. Add chopped onion and sauté for about 4 minutes until translucent. Add minced garlic and cook another minute. If using sausage, add it now, breaking up the meat, and cook until browned and cooked through. Next, stir in the bell pepper, dried sage, thyme, salt, and pepper, cooking for 2-3 minutes.
4. Combine Ingredients and Add Cheese:
Add the roasted squash to the skillet with the sausage and vegetables, gently tossing them together. Pour in the heavy cream and stir to coat the mixture. Remove the pan from heat, then stir in half of the mozzarella and Parmesan cheese.
5. Bake the Casserole:
Transfer everything into the prepared casserole dish and spread it out evenly. Sprinkle the remaining mozzarella and Parmesan cheese over the top. Bake in the preheated oven for 15-20 minutes until the cheese melts, bubbles, and turns slightly golden.
6. Serve and Enjoy:
Take the casserole out of the oven and let it cool just a bit. Garnish with fresh parsley for color and freshness, then serve warm. Enjoy your cozy and flavorful cheesy butternut squash casserole!
Can I Use Frozen Butternut Squash for This Casserole?
Yes, you can! Just make sure to thaw it completely and drain any excess moisture before roasting. This helps prevent the casserole from becoming too watery.
Can I Make This Casserole Ahead of Time?
Absolutely! Prepare the casserole up to step 12, cover it tightly, and refrigerate for up to 24 hours. When ready, add the remaining cheese on top and bake as directed.
What Can I Substitute for Italian Sausage?
If you prefer a vegetarian option, use sautéed mushrooms, lentils, or plant-based sausage. For a different meat flavor, cooked bacon or ground turkey works well too.
How Should I Store Leftovers?
Store any leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or microwave until warmed through.