Spaghetti Squash Lasagna Casserole

Trade out your traditional lasagna noodles for spaghetti squash in this easy spaghetti squash lasagna casserole! It’s made with just a few simple ingredients and is a great comfort food recipe. Vegan and vegetarian options included.

When you think of budget friendly dinners, spaghetti squash recipes likely don’t come to mind. After all, traditional pasta noodles are about as dirt cheap as white rice. You can even find fancier legume-based plant-based pasta brands for just a few dollars at most grocery stores these days. 

But when you can find spaghetti squash sold by the squash (not per pound) this winter squash is a great, affordable way to get additional veggies in during the colder months and early Spring. Each serving is just about $2.61 each with additional saving tips at the bottom of this post!

Ingredient Notes

• Spaghetti squash: For this lasagna, I prefer to use a roasted spaghetti squash because I find it to be more flavorful, but if you’re short on time, you can use my quick Instant Pot Spaghetti Squash recipe to cook the squash in 7 minutes. 
• Beef: This lasagna can be made with regular or a store-bought vegan beef. If you prefer a healthier option, try this Homemade Vegan Ground Beef Recipe. If you choose to use regular beef, use a lean beef (at least 85/15, ideally 93/7). Or, use a leaner meat like ground turkey or ground chicken. 
• Marinara sauce: You’ll need 1 (25-28 ounce) jar of marinara sauce. I’ve made this recipe using store-bought and homemade and prefer the flavor of my homemade pasta sauce. 
• Ricotta: We are lactose intolerant and make this lasagna with either my Tofu Ricotta or Cashew Ricotta made with fresh basil (seen in photos). If you tolerate dairy, feel free to use a dairy ricotta of choice. Dairy ricotta is about 1/2 the price of a dairy-free version!

 For full measurements and ingredients, scroll down to the recipe card at the bottom of this post. 

How to Make Spaghetti Squash Lasagna Casserole

1. Prep and cook the squash: Using a sharp knife, carefully halve the spaghetti squash lengthwise. Scoop the seeds and pulp from the center, then brush each halve with about 1 teaspoon of olive oil. Lightly season with kosher salt and black pepper, and place squash halves cut-side down on a large rimmed baking sheet (you may need 2 baking sheets).
   
   Bake in a preheated oven for 35-45 minutes, or until the spaghetti squash are easily pierced with a knife. Set aside to cool until easy enough to handle.
2. Cook the beef: While the squash roasts, cook the beef. Heat a large skillet over medium heat until warm, then add the remaining oil. Once warm, add in the beef along with the red pepper flakes and black pepper.
   
   Cook for 5-8 minutes, or until cooked through, breaking the beef up with a spatula as it cooks. If needed, drain any excess fat from the skillet. Then, add the marinara and continue to cook until warmed through and set aside.
3. Layer the lasagna: Once the squash is cool enough to handle, scrape the spaghetti squash strands and place ¼ of the spaghetti strands in the bottom of a greased 9×13 baking dish.
   
   Dollop on several spoonfuls of ricotta (about ¼-⅓ cup) followed by ¼ or ⅓ cup of the meat sauce. Repeat layering until all the ingredients are used up. Reduce the oven temperature to 375 degrees F.
4. Bake: Cover the baking dish with a sheet of foil and bake for 25 minutes. Uncover, and bake for a final 10 minutes.
5. Serve: Cool slightly, then serve while fresh with additional fresh chopped  basil, parmesan cheese and red pepper flakes, or as desired.

Serving Suggestions

Spaghetti squash lasagna is delicious served with a slice of hot and crusty garlic bread and a simple green salad. You can also serve with an array of roasted veggies, like Air Fryer Green Beans, Air Fryer Brussels Sprouts, and/or Cabbage Steaks. 

For more ideas, check out these 51 Sides and Salads to Serve with Spaghetti. 

Recipe FAQs

How do you keep spaghetti squash from getting soggy?

Because the marinara sauce and ricotta cheese mixture contain salt, it will naturally draw some of the moisture out of the spaghetti squash, resulting in a bit of water in the bottom of the casserole dish. This is very minimal and does not compromise the flavor at all. I regularly make this recipe for meal prep and find that the squash reabsorbs a lot of the moisture as it cools. Don’t worry if you see a little water at the bottom! 

Is cooked spaghetti squash supposed to be crunchy?

Cooked spaghetti squash should be firm, yet tender, similar to al dente pasta. It should not be crunchy or overly soft. When a spaghetti squash is ready, it should be easy to fork away from the sides of the squash. 

Can you eat the skin of a spaghetti squash?

The skin of a spaghetti squash is technically edible, but it is not enjoyable to eat. It’s tough and fibrous, and not appealing. Simply compost the skin, or chop it into small pieces and use it to make a flavorful homemade vegetable broth. 

Storage Instructions

Leftover lasagna can be stored directly in the baking dish, tightly covered with saran wrap or foil. Alternatively, transfer leftovers to an airtight container and store in individual servings.