Baked Spaghetti Squash Casserole
This cheesy Spaghetti Squash Casserole is cozy, hearty, and packed with hidden veggies. It features roasted spaghetti squash, spicy Italian sausage, lots of aromatics, and a rich tomato basil sauce. It’s folded together with creamy Greek yogurt and parmesan, then topped with melty mozzarella cheese. Every bite is savory, cheesy, and comforting—but still light and nutritious.
Servings: 6 people
Ingredients
- 1 large yellow spaghetti squash, about 4 pounds whole, halved & seeds removed
- 1 Tablespoon olive oil
- 1 pound ground spicy Italian sausage
- 1 8 ounce container white mushrooms, finely diced
- 1 yellow onion, diced
- 5 cloves garlic, minced*
- 1 teaspoon salt
- 5 cracked black pepper
- 1 teaspoon dried thyme
- 1 teaspoon dried oregano
- 1/2 teaspoon red chili flakes*
- 1/4 teaspoon dried rosemary
- 1 25 ounce jar tomato basil pasta sauce*
- 1/2 cup plain greek yogurt*
- 1 ounce (1/3 cup) parmesan reggiano grated
- 6 ounces (1 1/2 cups) mozzarella cheese, shredded
- fresh basil for garnishing
Instructions
- Prep Squash: Preheat the oven to 400 degrees. On a baking sheet lined with parchment paper, brush all sides of the spaghetti squash with oil. Place squash halves cut-side down.1 large yellow spaghetti squash, about 4 pounds whole, halved & seeds removed, 1 Tablespoon olive oil
- Bake Squash & Make Meat Sauce: Bake for 40-60 minutes, or until fork tender. While the squash bakes, in a large pot over medium-high heat, cook the sausage and mushrooms. Let most of the water evaporate from the mushrooms.1 pound ground spicy Italian sausage, 1 8 ounce container white mushrooms, finely diced
- Sauté Aromatics: Add the onions, garlic, and spices. Cook for 3-4 minutes or until the onion softens.1 yellow onion, diced, 5 cloves garlic, minced*, 1 teaspoon salt, 5 cracked black pepper, 1 teaspoon dried thyme, 1 teaspoon dried oregano, 1/2 teaspoon red chili flakes*, 1/4 teaspoon dried rosemary
- Simmer the Sauce: Add the sauce and simmer on medium-low heat, stirring frequently until the squash is done. The sauce should thicken up a bit.1 25 ounce jar tomato basil pasta sauce*
- Create Spaghetti: Once the squash is done, let it cool until you can handle it. Use a fork to scrape the middle of the squash so that the spaghetti-like strands form.
- Assemble the Casserole: Fold the squash, yogurt, and parmesan cheese into the meat sauce.1/2 cup plain greek yogurt*, 1 ounce (1/3 cup) parmesan reggiano
- Prep for Baking: Lightly grease a 9 x 13 baking dish. Pour the squash mixture into the dish. Sprinkle the mozzarella cheese on top.6 ounces (1 1/2 cups) mozzarella cheese, shredded
- Bake the Squash: Bake for 15 minutes, or until the edges are bubbling and the cheese is completely melted. Let stand for 5-10 minutes before serving.fresh basil for garnishing
Notes
- Garlic: Fresh minced garlic offers the best flavor, but 5 teaspoons of garlic paste or pre-minced garlic works too.
- Kosher Salt: All of my recipes are tested with Morton kosher salt unless noted otherwise. It is the best salt for everyday cooking because of its size and flavor. If using table salt, the amount should be reduced. I highly recommend picking up some kosher next time you are at the store!
- Red Chili Flakes: Adds a touch of heat. Omit for a milder dish or increase for extra spice.
- Tomato Basil Pasta Sauce: A jarred shortcut that keeps things simple. Use your favorite brand or homemade marinara.
- Plain Greek Yogurt: Adds creaminess and a tangy finish without heavy cream. Half a cup of sour cream or whole milk ricotta is a good substitute.
- Let the Squash Cool Slightly: It’ll be much easier to handle when scooping the strands.
- Don’t Skip Resting: Letting the casserole sit helps it set and makes serving cleaner.
Nutrition
Serving: 1serving | Calories: 511kcal | Carbohydrates: 27g | Protein: 25g | Fat: 35g | Saturated Fat: 14g | Polyunsaturated Fat: 4g | Monounsaturated Fat: 15g | Trans Fat: 1g | Cholesterol: 84mg | Sodium: 1861mg | Fiber: 6g | Sugar: 13g