Save The first time I made this casserole, it was supposed to be a quick weeknight dinner but ended up being the meal that convinced my squash-hating roommate that she actually loved butternut squash. There is something magical about how the sweetness of roasted squash plays against savory sausage, especially when everything gets bubbly under a blanket of melted cheese. This is the kind of dish that makes your entire kitchen smell like autumn comfort.
I brought this to a potluck last winter and watched three different people ask for the recipe. The best part was that I had prepped it the night before, so I just popped it in the oven when I arrived. Something about casserole dishes makes people immediately feel at home, like they are walking into their grandmothers kitchen.
Ingredients
- 1 medium butternut squash: Peeled, seeded, and cut into 1-inch cubes because smaller pieces cook faster and get more caramelized edges
- 1 medium onion: Diced small so it melts into the background rather than staying in distinct chunks
- 2 cloves garlic: Minced fresh, never jarred, because the difference in aroma is worth the extra minute
- 3 cups baby spinach: It looks like too much but wilts down to almost nothing, adding color and nutrition
- 1 pound Italian sausage: Sweet or spicy works, just remove the casing so it can crumble beautifully
- 1 cup cooked quinoa: Adds nutty flavor and makes the casserole feel substantial without being heavy
- 1 cup shredded mozzarella cheese: Low moisture cheese melts better without making the dish watery
- ½ cup grated Parmesan cheese: The salty punch that balances the sweet squash
- 2 tablespoons olive oil: Use a light olive oil that can handle medium heat without burning
- 1 teaspoon dried thyme, sage, and paprika each: This trio creates that classic autumn herb profile
- Salt and pepper: Taste before baking because the cheese and sausage already bring salt
- 1 cup chicken or vegetable broth: Creates steam while baking to help the squash finish cooking
Instructions
- Get your oven ready:
- Preheat to 375°F and grease a 9x13-inch baking dish with cooking spray or olive oil, paying attention to the corners where things love to stick.
- Sauté the aromatics:
- Heat olive oil in a large skillet over medium heat and cook the diced onion for about 5 minutes until translucent, then add garlic for just 1 minute until fragrant.
- Brown the sausage:
- Crank up the heat slightly, add the crumbled sausage, and cook for 7 to 10 minutes while breaking it apart with a wooden spoon until browned and cooked through.
- Add the squash and spices:
- Toss in the cubed butternut squash with thyme, sage, paprika, salt, and pepper, cooking for 5 to 7 minutes until the squash starts to soften at the edges.
- Wilt in spinach and quinoa:
- Stir in baby spinach and cooked quinoa, cooking just until the spinach collapses into the mixture.
- Add moisture:
- Pour in the broth and let everything simmer for 3 to 4 minutes while scraping up any browned bits from the bottom of the pan.
- Assemble and bake:
- Transfer the mixture to your prepared baking dish, spread it evenly, and cover with both cheeses. Bake covered with foil for 25 minutes, then uncovered for 15 to 20 minutes until the cheese is golden and bubbling.
- Rest and serve:
- Let the casserole cool for 5 minutes so portions hold together better when you scoop them.
Save My sister called me mid-bite once to say this was the first time her toddler had ever willingly eaten squash. The cheese helps, obviously, but there is something about the combination of flavors that works even for picky eaters who claim to hate vegetables.
Make Ahead Magic
You can assemble everything up to 2 days before baking and keep it covered in the refrigerator. The flavors actually meld together beautifully during this rest period, though you will need to add about 10 extra minutes to the covered baking time if it goes in cold.
Vegetarian Twist
Plant-based sausage works surprisingly well here, or you can use a combination of white beans and mushrooms for a hearty vegetarian version. The spices and squash provide so much flavor that you honestly will not miss the meat.
Serving Suggestions
A crisp green salad with vinaigrette cuts through the richness, and crusty bread is perfect for soaking up any cheesy juices. A light Pinot Noir or Sauvignon Blanc complements the savory flavors without overwhelming the dish.
- Let it rest longer than you think you should before serving
- The cheese continues bubbling for several minutes after leaving the oven
- Serve directly from the baking dish to keep the warmth
Save This casserole is what comfort food should be, satisfying without leaving you feeling weighed down, and the kind of recipe that somehow makes a Tuesday dinner feel special.
Kitchen Guide
- → Can I make this butternut squash casserole ahead of time?
Yes, you can assemble the entire dish up to 2 days before baking. Store it covered in the refrigerator and add a few extra minutes to the baking time if cooking from chilled. The flavors actually develop and meld together even better when made ahead.
- → What can I substitute for the Italian sausage?
For a vegetarian option, use plant-based sausage crumbles or cannellini beans. You could also use ground turkey, chicken, or even crumbled tofu with extra Italian herbs to maintain the savory protein element.
- → Is this casserole gluten-free?
The dish is naturally gluten-free when using certified gluten-free sausage and broth. Quinoa is a gluten-free grain, but always check labels on processed ingredients like sausage and broth to ensure they don't contain hidden gluten.
- → How do I store and reheat leftovers?
Store leftovers in an airtight container in the refrigerator for 3-4 days. Reheat individual portions in the microwave at 50% power to prevent the cheese from separating, or cover with foil and reheat in a 350°F oven until warmed through.
- → Can I freeze this butternut squash and sausage bake?
Yes, this freezes well. Assemble the dish without the cheese topping, wrap tightly, and freeze for up to 3 months. Thaw overnight in the refrigerator, add the cheese, and bake as directed. You may need slightly more time if baking from partially frozen.
- → What sides pair well with this casserole?
A simple green salad with vinaigrette balances the richness. Crusty bread works well for soaking up the flavorful juices. For a complete meal, serve with roasted Brussels sprouts or steamed green beans. A light red wine like Pinot Noir complements the savory sausage beautifully.