Vegetarian Spaghetti Squash Lasagna is a lighter, vegetable-packed alternative to classic lasagna. Serve it with crusty bread for a warm, satisfying dinner.
This Vegetarian Spaghetti Squash Lasagna swaps pasta sheets for roasted spaghetti squash, layering tender squash strands with creamy ricotta, sautéed vegetables, marinara, and melted Italian blend cheese. The result is familiar lasagna flavor with fewer carbs and more vegetables, making it a great option when you want something comforting but a little lighter.
It takes a bit more time than a simple weeknight meal because the squash needs to roast, but the hands-on steps—sautéing the vegetables and assembling the layers—make it a rewarding weekend cooking project. The techniques are straightforward: roast the squash whole, remove excess moisture from the strands, gently cook the vegetables so they don’t release excess liquid, and layer everything in an 8×8 dish.
Ingredients
- 1 medium spaghetti squash
- 1 tablespoon olive oil
- 1 shallot, minced
- 10 oz button mushrooms, chopped
- 1 red pepper, cut into ½-inch dice
- 1 (6 oz) bag baby spinach
- ½ teaspoon dried oregano
- ½ teaspoon red pepper flakes
- 1 teaspoon kosher salt, divided
- 15 oz ricotta
- ¼ cup milk (or 1 egg, optionally)
- 1 oz fresh basil, chiffonade
- 1¼ cups marinara sauce
- 1½ cups shredded Italian blend cheese, divided
How to make vegetarian spaghetti squash lasagna
Preheat your oven and roast the whole spaghetti squash. Roasting it whole helps retain moisture and keeps the flesh tender. Depending on the squash size, roasting usually takes 60–75 minutes. Let it cool long enough to handle, then cut it open, scoop out the seeds, and use a fork to release the spaghetti-like strands.
One key step is removing excess water from the squash strands so the lasagna doesn’t turn out soupy. Put the cooked strands into a clean tea towel and wring firmly over the sink until no more liquid comes out. Toss the drained strands with half of the kosher salt to season.
While the squash roasts, sauté the vegetables. Heat the olive oil in a large sauté pan over medium heat. Cook the minced shallot and chopped mushrooms until the mushrooms are soft and most of their liquid has evaporated. Add the diced red pepper and cook 3–4 minutes more until tender, then add the spinach and cook until wilted. Stir in the oregano, red pepper flakes, and the remaining salt to finish the vegetable mixture. Cook long enough to reduce moisture but avoid overcooking so the vegetables remain flavorful.
For the ricotta layer, mix the ricotta with ½ cup of the shredded Italian blend cheese, the milk (or beaten egg if you prefer), and the fresh basil. The milk keeps the ricotta creamy and vegetarian-friendly; an egg can be used instead if you prefer a firmer filling.
Assembling the lasagna
Grease an 8×8-inch baking dish. Spread ½ cup marinara sauce across the bottom of the dish to prevent sticking and to add moisture. Layer the components as follows to build three even layers:
- Spread ½ cup marinara sauce on the bottom.
- Add ⅓ of the drained spaghetti squash.
- Spoon on ½ of the ricotta mixture and spread evenly.
- Top with ½ of the sautéed vegetables.
- Add another ⅓ of the spaghetti squash.
- Spread the remaining ricotta mixture.
- Add the remaining vegetables.
- Finish with the last ⅓ of spaghetti squash.
- Pour the remaining marinara over the top and sprinkle with the remaining shredded Italian blend cheese.
Cover the dish with foil—if the cheese is very close to the foil, place a few toothpicks into the top of the lasagna to keep the foil from touching the cheese. Bake at 375–400°F (see recipe times below) until heated through, about 30 minutes covered. Remove the foil and broil for 6–8 minutes, watching carefully, until the cheese is bubbly and golden in spots. Let rest 10 minutes before slicing to allow the layers to set.
This lasagna pairs nicely with a crisp green salad or roasted potatoes and sliced French bread for a heartier meal.
Recipe
Vegetarian Spaghetti Squash Lasagna
Prep time: 45 mins · Cook time: 1 hr 45 mins · Total time: 2 hrs 30 mins · Servings: 6 · Calories: 309 kcal
Instructions
- Preheat the oven to 375°F. Poke holes in the whole spaghetti squash and place on a baking sheet. Roast 60–75 minutes until tender. Remove and let cool slightly, then cut in half and remove the seeds.
- Heat olive oil in a large sauté pan over medium heat. Add the minced shallot and chopped mushrooms and cook until the mushrooms have softened and released their liquid.
- Add the diced red pepper and cook 3–4 minutes until softened. Add the spinach and cook until wilted.
- Season the vegetables with ½ teaspoon oregano, ½ teaspoon red pepper flakes, and ¼ teaspoon salt (or as directed in the ingredient list).
- Use a fork to scrape the squash flesh into strands. Place the strands in a clean tea towel and wring out excess water until no more liquid escapes. Transfer the drained strands to a bowl, season with ½ teaspoon salt, and toss.
- Combine the ricotta, ½ cup of the shredded Italian blend cheese, milk (or egg), fresh basil, and the remaining ¼ teaspoon salt in a bowl and stir until smooth.
- Raise the oven temperature to 400°F. Grease an 8×8-inch baking dish. Pour ½ cup marinara into the bottom and layer according to the assembling steps listed above.
- Cover with foil and bake 30 minutes. Remove foil and broil 6–8 minutes until the cheese is golden in spots. Let cool 10 minutes, garnish with extra basil, slice, and serve.
Notes
Tip: An offset spatula makes it easier to spread the ricotta evenly between layers. Removing as much liquid as possible from both the roasted squash and the sautéed vegetables prevents a watery lasagna.
Nutrition
- Calories: 309 kcal
- Carbohydrates: 21 g
- Protein: 19 g
- Fat: 18 g
- Saturated Fat: 10 g
- Cholesterol: 55 mg
- Sodium: 950 mg
- Potassium: 819 mg
- Fiber: 5 g
- Sugar: 10 g
- Vitamin A: 4460 IU
- Vitamin C: 42 mg
- Calcium: 459 mg
- Iron: 3 mg
If you try this recipe, please leave a comment to share how it turned out—feedback helps others find and enjoy this lighter lasagna option.
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