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!
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.