Cheesy Vegetarian Spaghetti Squash Casserole Recipe - Peas and Crayons (2024)

5 from 15 votes

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Servings: 4 servings

Author: Jenn Laughlin – Peas and Crayons

• 1 large spaghetti squash (approx. 3 lbs)
• 1-2 tsp olive oil
• ½ cup onion
• 1-2 cloves garlic, smashed and minced
• 5 oz mushrooms (2 cups chopped)
• 2-3 oz fresh spinach (1.5 cups chopped)
• 1 plum tomato, chopped
• 1.5 cups ricotta cheese
• 1 egg white (optional)
• ⅔ cup freshly grated parmesan cheese
• 1-2 tsp Italian seasoning blend (I love Mrs. Dash)
• ½ tsp dried basil
• ½ tsp garlic powder
• salt and pepper, to taste
• ½ cup spaghetti sauce
• 2 oz grated mozzarella
• ¼ tsp crushed red pepper flakes
• 1 TBSP chopped parsley (optional garnish)

• Pre-heat oven to 400 degrees F.

• Slice your spaghetti squash in half lengthwise and scoop out the seeds.For easy cutting, you can poke a few holes in the squash and microwave it whole for 4-5 minutes to soften it up just a tad. The knife slides through much easier this way!

• Rub the cut side of the squash with a teeny bit of olive oil and place on a lipped baking sheet and roast face-down for about 40 minutes, or until tender and easily pierced with a fork.Cooking time will vary a bit depending on the size of your squash so adjust accordingly. Once ready, the once rock-hard exterior of the squash will be visibly softened with a tender interior.

• While the squash roasts, prep your cheese and veggies.

• Chop your onion, garlic, mushrooms, spinach and tomato, separately, then set aside.

• Bring a pan or skillet to medium-high heat with a drizzle of olive oil and sauté onion until tender and slightly golden, then add garlic and mushrooms and continue to cook until softened. Set aside.

• In a large bowl, combine ricotta, egg white, freshly grated parmesan cheese, fresh chopped spinach, Italian seasoning, basil, and garlic powder.

• Drain your mushroom/onion mixture and add to the bowl along with your chopped tomato.Mix well, adding a little salt and pepper to taste.

• Once your squash is ready, allow to cool slightly, then use a fork to separate the squash’s interior into spaghetti-like strands.

• Next spritz a baking dish with olive oil and add your forked strands of spaghetti squash, top with cheese and veggie filling and mix.

• Add a layer of red sauce and top with mozzarella cheese (as much or as little as your heart desires of each) and an optional pinch of red pepper flakes (skip if sensitive to heat) and bake at 350 F until hot and bubbly, approx. 20-25 minutes.

• For golden flecks of mozzarella, switch oven to broil on HIGH for 2 minutes at the end and remove once bubbling.

• Garnish with parsley, if desired and serve piping hot with a healthy side salad or roasted veggies for a balanced meal that’s sure to rock your plate!Enjoy!