Forget sweater weather, casserole weather is back! Cheesy Spaghetti Squash Casserole puts a healthy spin on family lasagna. Low carb, grain free spaghetti squash “noodles” pair perfectly with Italian favorites like sausage, tomato, and not one, not two, but three melty cheeses!
Whether you’re keeping it keto or going grain free, you’re probably no stranger to swaps. (Cauliflower rice, anyone?) But pasta is particularly difficult to “replicate.” That’s why I stopped thinking of my vegetables as substitutes and embraced them wholeheartedly as much as any other meal component.
This baked spaghetti squash casserole is a delicious homage to baked pasta dishes. You’ve probably had million dollar spaghetti casserole before, but have you ever had million dollar spaghetti squash casserole? Well, you’re about to… again and again and again.
Are you going to miss the noodles? Only if you let yourself. This (nearly) keto spaghetti squash casserole isn’t a “poor man’s version” – it’s doing its own bubbly, melty, cheesy, saucy thing. But if you need to baby-step it up, feel free to try our Crockpot bolognese over spaghetti squash. An equally satisfying gateway “substitute” meal.
For a condensed post, click to view the web story for this healthy casserole recipe!
Spaghetti Squash Casserole – Better Than Lasagna?
Well, maybe not “better,” but “better depending on your, mood, diet, palate, and/or the contents of your pantry.”
You know I love pasta – I’m an aficionado, a connoisseur, a devotee – but honestly, sometimes even I need a break from the heaviness, especially the kind that comes along with a cheesy baked pasta casserole, like baked ziti or lasagna.
Spaghetti squash noodles are the perfect foil for the richness of the meat, cheese and sauce in this spaghetti squash lasagna recipe. All the satisfaction, none of the bellyaches.
How to Make Spaghetti Squash Lasagna
Switch it up with squash! Everyone loves a pasta bake, but not everyone loves pasta – or how it makes them feel. This grain free, gluten free Spaghetti Squash Lasagna Casserole satisfies with way less carbs. Bonus: it’s veggie-forward without being vegetarian so you can literally sneak nutrients in under your kids noses.
- PREP. Roast squash until tender, remove flesh and set aside. Combine ricotta, parmesan, and 1 c mozzarella in a bowl and set aside.
- COOK. Saute sausage and beef in a skillet over medium high heat, stirring to break into crumbles. Add onion and cook until soft. Add garlic and cook 1 minute more. Work in tomato paste, then add crushed tomatoes and seasoning. Simmer 15 minutes, then stir in squash and basil.
- BAKE. Spread ⅓ of the squash mixture in a casserole dish and top with half the cheese mixture. Repeat this step, then top with the final third of the squash mixture. Sprinkle rest of mozzarella on top. Cover and bake at 400°F for 20 minutes. Remove foil and bake 5 minutes more, to brown cheese.
- SERVE. Garnish liberally with fresh herbs and serve.
- This casserole works best with “dry” spaghetti squash noodles – that means roast, don’t steam, your squash. If you do wind up with excess moisture, strain in a colander or use paper towels to dry.
- The portion sizes are generous! Plan ahead for leftovers (it stores very well in the refrigerator) or plan on a crowd (it won’t be hard!).
Make It Your Way
Swap the meat. Use ground turkey in place of ground beef or ground turkey sausage in place of pork sausage to reduce fat – but not flavor – in this low carb casserole recipe.
Swap the cheese. Swap half the mozzarella for fontina or provolone – there’s some latitude here, just make sure it’s melty!
Add (more) veggies. Make it greener! Add 1 16-oz package of defrosted frozen spinach to the ground beef mixture in step 4 (see recipe card below), before adding the crushed tomatoes. Mushrooms are also a delicious addition! Saute them in the pot first, remove using a slotted spoon, then fold the sauteed mushrooms into the sauce during step 4. (If you need a primer on sauteed mushrooms, click to read our guide on how to cook mushrooms!).
Frequently asked questions
As long as you cook the spaghetti squash correctly, definitely not! We recommend oven baking the squash over steaming in the Instant Pot or slow cooker.
Though higher in fat and protein, this lasagna casserole does clock in with 21g net carbs per serving. This veggie version is suitable for low carb diets and provides more nutrients than a traditional pasta dish.
While I don’t subscribe to the notion of “healthy vs unhealthy” (it’s all good in moderation!) you’re going to get plenty of veggies and protein in the dish. Healthy or not is up to you!
It’s not recommended. The combination of dairy and delicate spaghetti squash noodles means that a grainy, watery casserole is in your future after defrosting. That being said, you can absolutely freeze the sauce for a partially make-ahead meal!
More Super Squash Recipes
- Sausage Stuffed Acorn Squash
- Healthy Tuscan Chicken Over Spaghetti Squash
- Butternut Squash Panzanella
- Honeynut Squash Rice Pilaf
- Roasted Delicata Squash Salad
Did you make this spaghetti squash casserole? I’d love to know how how turned out! Leave a comment and a rating below.
Spaghetti Squash Casserole (Lasagna Style)Print Recipe Rate this Recipe Pin Recipe
- 9×13 Casserole Dish
Roasted Spaghetti Squash
- 2 small spaghetti squash
- 1 tbsp olive oil
- ½ tsp kosher salt
- ½ tsp ground pepper
Spaghetti Squash Casserole
- 1 lb italian sausage
- 1 lb ground beef
- 1 medium sweet onion, diced to ½”
- 4 cloves garlic
- 1 6- oz can tomato paste
- 28 oz crushed tomatoes
- 1 tsp kosher salt
- 2 tsp italian seasoning
- 2 tbsp chopped basil, divided
- 2 c ricotta cheese
- 2 c shredded mozzarella cheese
- ½ c parmesan cheese
Roasted Spaghetti Squash
- Heat oven to 425°F. Line a baking sheet with parchment paper.
- Slice the squash in half lengthwise, then scoop out the seeds. Rub all over with the olive oil, then season the flesh with salt and pepper.
- Lay the squash cut side down on the prepared baking sheet and roast until the flesh is tender and the top is caving in, 30-35 minutes for smaller squash, 40-45 minutes for larger squash. Allow to cool for five minutes, then gently flake the squash strands from the skin using a fork.
Spaghetti Squash Casserole
- While the squash cooks, prepare the meat sauce. Cook the italian sausage and ground beef in a 6-quart dutch oven over medium high heat until no longer pink, stirring to break into crumbles, 10-12 minutes.
- Add the onion; cook until softened, 5-6 minutes. Add the garlic and cook 1 minute more.
- Work tomato paste into the mixture, stirring constantly for 2-3 minutes to work off the canned flavor. Add the crushed tomatoes, salt, pepper, and italian seasoning. Simmer 15 minutes.
- Remove from heat and stir in the squash flesh and 1 tablespoon chopped basil.
- Combine the ricotta cheese, 1 c mozzarella, and parmesan cheese in a small bowl.
- Spread ⅓ of the squash and meat mixture over the bottom of a casserole dish. Dollop half the ricotta mixture over the top. Add another third of the squash mixture, then dollop the remaining ricotta mixture on top. Top with the final third of the squash mixture, then sprinkle the rest of the mozzarella cheese over the casserole.
- Cover and bake at 400°F for 20 minutes. Remove the foil and bake 5 minutes more, until cheese is lightly browned and the casserole is bubbling.
- Garnish liberally with the remaining fresh basil and serve.