Spaghetti Squash Casserole with Ground Beef
This Spaghetti Squash Casserole is my idea of healthy comfort food — it’s cozy, hearty, and made with real ingredients. It has all the flavor of a classic pasta bake, but with tender spaghetti squash, a savory beef and mushroom tomato sauce, and just enough melted cheese to bring it all together.
This Spaghetti Squash Casserole recipe is healthy comfort food at its best. Tender strands of roasted spaghetti squash are tossed with a savory tomato-beef sauce, mushrooms, herbs, and topped with melted cheese for a cozy, satisfying dinner that feels indulgent.
Once the squash is cooked, everything comes together in one pot, making this an easy, nourishing meal for busy weeknights.
It’s reminiscent of my spaghetti squash lasagna, but that recipe includes more cheese and its baked right in the the halved, cooked spaghetti squash.
The best part about this is that the spaghetti squash can be cooked up to a few days in advance to make this a true one pot dinner on busy nights.
Serve it with a simple arugula and fennel salad or a side of air fryer roasted vegetables for the perfect dinner!
Why you’ll love this recipe
- This low carb casserole with ground beef is a comforting, high-protein dinner that’s perfect for cold winter months.
- When you want veggie-forward comfort food (without the heavy pasta!), this is the recipe for you.
- This is a quick and easy dinner. Once the spaghetti squash is cooked, the rest cooks up quickly in one pot on the stove top, then it’s baked in the oven.
- The spaghetti squash can be cooked up to a few days in advance to make this meal go very quickly on busy nights.
Recipe ingredients
This recipe includes just a few basic ingredients that can be easily customized with what you have on hand.
- Spaghetti squash. A 2 lb. spaghetti squash yields 3 cups of cooked squash. There are a few different cooking methods for spaghetti squash (see my post how to cook spaghetti squash for more information). My preferred method is roasting it in the oven, as it keeps moisture down and the squash gets nice and caramelized. You can also drain the squash to remove excess liquid as needed.
- Ground beef. Use 1 lb. lean ground beef for this recipe, which significantly cuts down the amount of fat in casserole.
- Aromatics. Onion and garlic add a great flavor base.
- Mushrooms. Add meaty flavor and bulk up the casserole, which makes it even more satisfying. You can certainly omit them if you’re not a fan of mushrooms.
- Tomato sauce and diced tomatoes. Creates a saucy base that keeps the casserole moist. Use fire roasted diced tomatoes for extra flavor!
- Tomato paste. Helps thicken the sauce and adds rich, savory tomato flavor.
- Dried herbs. I love using Italian seasoning here, or you can sub with herbs de provence, dried basil, thyme and more.
- Balsamic vinegar. Adds acidity and savory depth of flavor. Optional but highly recommended!
- Mozzarella cheese. Use part-skim or whole milk mozzarella as desired. I recommend grating it yourself for better meltability, as pre-grated cheese is coated with anti-caking agents to keep it from sticking together. Sub with your favorite variety of cheese!
See the recipe card below for the full list of ingredients and quantities.
Swaps & Variations
- Make it lighter. Use part-skim mozzarella or reduce the cheese slightly.
- Prefer a different protein? Ground turkey or chicken works well, though beef provides the richest flavor. Italian sausage is another flavorful option.
- Make it vegetarian. Omit the ground beef and add additional chopped veggies like bell pepper or zucchini and add a can of your favorite beans. You can also stir in spinach or kale at the end just until wilted.
- Make it dairy-free. Skip the cheese or use a dairy-free shredded alternative.
- Add some heat. Add red pepper flakes or a pinch of cayenne to the sauce.
How to make this recipe
This spaghetti squash casserole with ground beef is a very easy recipe to prepare. The squash must be cooked first, and I’ve linked my handy post on how to cook spaghetti squash in the recipe card so that you can choose the method that you prefer.
I love roasting the squash in the oven to achieve caramelizing and cut down on moisture as the squash can get a bit watery or mushy.
Once it’s cooked, its shredded and set aside until the saucy beef and mushroom mixture is prepared on the stove top.
From there, the squash is added, the mixture is covered with cheese, and baked until bubbly and golden in the oven.
Pro tip: Cook the spaghetti squash 1-2 days in advance to make this recipe go quicker on busy nights. Drain the spaghetti squash well to remove any excess moisture.
See the recipe card below for full instructions.
Recipe FAQs
Spaghetti squash can be cooked in the microwave, Instant Pot, slow cooker and roasted in the oven. See my post on how to cook spaghetti squash for more information.
I recommend roasting the spaghetti squash in the oven for the best texture. Roasting caramelizes the squash for great flavor, and reduces excess moisture and helps keep it from becoming mushy.
It’s normal that to have some moisture, so simply drain the squash well before adding it your dishes.
Yes! It can be baked, then cooled completely and stored in the refrigerator for up to 3 days. Reheat in the microwave.
Serving suggestions
This casserole is plenty hearty enough to stand alone but pairs well with the following recipes:
- Keep it lower carb by serving it with a fresh Italian tricolore salad or spring mix salad.
- Serve it with extra veggies such as air fryer brussels sprouts or roasted cauliflower with parmesan.
- A slice of one hour rosemary focaccia bread or your favorite crusty bread is perfect for dunking.
Recipe notes
- Pro tip: Cook the spaghetti squash 1-2 days in advance to make this recipe go quicker on busy nights. Drain the spaghetti squash well to remove any excess moisture.
- For best results, roast the spaghetti squash in the oven for caramelization and to reduce excess moisture.
- The spaghetti squash casserole can be assembled in advance and baked when you’re ready.
- Store leftovers in the refrigerator for up to 3 days.
More casserole recipes you’ll love
- Cabbage and ground beef casserole
- Crock pot chicken and wild rice casserole
- Ground beef enchilada casserole
- One pot stuffed pepper casserole
Did you try this recipe? If so, be sure to leave a review below and tag me @flavorthemoments on Facebook and Instagram
Spaghetti Squash Casserole
Ingredients
- 2 lbs. spaghetti squash
- 1 tbsp. olive oil
- 1 lb. lean ground beef
- 1 onion chopped
- 8 oz. baby bella mushrooms sliced
- 3 cloves garlic
- 2 tbsp. tomato paste
- 1 tsp. Italian seasoning sub with your favorite dried herbs
- 15 oz. tomato sauce
- 15 oz. fire roasted diced tomatoes
- 1 tbsp. balsamic vinegar
- salt and pepper, to taste
- 1.5 cups grated mozzarella cheese sub with your favorite
- freshly chopped parsley, for garnish optional
Instructions
- See my post on how to cook spaghetti squash and cook it using your preferred method. Allow the squash to cool slightly, then shred with a fork and place in a bowl. You will have roughly 3 cups of spaghetti squash. You can also cook the squash up to a few days in advance to make this recipe go quickly on busy weeknights. Drain the squash well as needed prior to adding it to the casserole mixture.2 lbs. spaghetti squash
- Preheat the oven to 400 degrees. Heat the olive oil in a large oven proof skillet over medium heat. Add the ground beef and break up into chunks. Cook about 2 minutes, then add the onions and mushrooms and cook until the mushrooms have released their liquid. Add the garlic, herbs and tomato paste and cook 30 seconds longer.1 tbsp. olive oil, 1 lb. lean ground beef, 1 onion, 8 oz. baby bella mushrooms, 3 cloves garlic, 2 tbsp. tomato paste, 1 tsp. Italian seasoning
- Add the tomato sauce, diced tomatoes and balsamic vinegar and bring to a boil. Reduce the heat to medium low and cook for 5 minutes. Remove from heat and season with salt and pepper to taste.15 oz. tomato sauce, 15 oz. fire roasted diced tomatoes, 1 tbsp. balsamic vinegar, salt and pepper, to taste
- Stir in the 3 cups of cooked spaghetti squash and top with the grated cheese. Bake for 20 minutes or until bubbly and the top is golden brown. Remove from heat, let stand for 5 minutes, then serve. Garnish with parsley as desired and enjoy!1.5 cups grated mozzarella cheese, freshly chopped parsley, for garnish
Notes
- Pro tip: Cook the spaghetti squash 1-2 days in advance to make this recipe go quicker on busy nights. Drain the spaghetti squash well to remove any excess moisture.
- For best results, roast the spaghetti squash in the oven for caramelization and to reduce excess moisture.
- The casserole can be assembled in advance and baked when you’re ready.
- Store leftovers in the refrigerator for up to 3 days.
Nutrition
Nutrition is estimated using a food database and is only intended to be used as a guideline for informational purposes.
