Vegetarian Mushroom and Spinach Lasagna is the comfort food answer to busy weeknights when you need something hearty but don’t want to spend hours in the kitchen. This recipe layers tender pasta with a savory mushroom-spinach filling and creamy cheese that melts into every bite.
Table of Contents
Ingredients for Vegetarian Mushroom and Spinach Lasagna
I’ve made this lasagna more times than I can count, and the ingredient quality really matters here. I prefer whole milk ricotta because it stays creamier during baking, and cremini mushrooms give you that deeper, earthier flavor that makes people think you spent all day cooking.
- 9 lasagna noodles
- 1 pound cremini or button mushrooms (sliced) – Cremini have more flavor, but button mushrooms work perfectly fine
- 6 cups fresh spinach (or 10 oz frozen spinach, thawed and squeezed dry)
- 1 medium onion (diced)
- 3 cloves garlic (minced) – Fresh garlic is worth it here for the aroma
- 2 cups whole milk ricotta cheese – I usually let it sit in a strainer for 15 minutes if it looks watery
- 1⅔ cups shredded mozzarella cheese (divided: ⅔ cup for layering, 1 cup for topping)
- ½ cup grated Parmesan cheese – Freshly grated melts better than pre-shredded
- 3 cups marinara sauce (your favorite jarred brand or homemade)
- 2 tablespoons olive oil
- 1 teaspoon dried Italian seasoning
- Salt and black pepper to taste
Step-by-Step Instructions
The secret to lasagna that holds together when you slice it is letting it rest for a full 10 minutes after baking. I know it’s tempting to dig in right away, but trust me on this one.
Step 1: Preheat your oven to 375°F. Cook the lasagna noodles according to package directions until al dente (usually 8-10 minutes), then drain and lay them flat on a baking sheet drizzled with olive oil to prevent sticking. This step is important because sticky noodles tear when you try to layer them.
Step 2: While noodles cook, heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the diced onion and cook for 3-4 minutes until softened and translucent. Add the minced garlic and cook for another 30 seconds until fragrant but not browned.
Step 3: Add the sliced mushrooms to the skillet and cook for 8-10 minutes, stirring occasionally, until they’ve released their moisture and the liquid has evaporated. The mushrooms should be golden brown and the pan should look fairly dry. Add the spinach in batches if using fresh, stirring until wilted (about 3-4 minutes total). If there’s excess liquid in the pan, drain it off to prevent a watery lasagna. Season with Italian seasoning, salt, and pepper. Remove from heat and set aside.
Step 4: In a 9×13-inch baking dish, spread 1 cup of marinara sauce evenly across the bottom. This prevents the bottom noodles from sticking and adds moisture. Layer 3 lasagna noodles over the sauce, slightly overlapping if needed depending on your noodle brand.
Step 5: Spread half of the ricotta cheese over the noodles using the back of a spoon, then top with half of the mushroom-spinach mixture, spreading it evenly. Sprinkle with ⅓ cup mozzarella and 2 tablespoons Parmesan. Pour 1 cup of marinara sauce over the cheese layer, spreading gently to cover.
Step 6: Repeat the layering process: 3 noodles, remaining ricotta, remaining mushroom-spinach mixture, ⅓ cup mozzarella, 2 tablespoons Parmesan, and 1 cup marinara sauce. Make sure to spread each layer evenly so every bite has all the components.
Step 7: Top with the final 3 lasagna noodles, spread the remaining marinara sauce over them completely (exposed noodles will become hard and chewy), and finish with the remaining 1 cup mozzarella and remaining Parmesan cheese.
Step 8: Cover the baking dish tightly with aluminum foil (spray the underside with cooking spray to prevent the cheese from sticking to the foil) and bake for 25 minutes. Remove the foil and bake for an additional 15-18 minutes until the cheese is golden brown and bubbly around the edges. Let the lasagna rest for 10 minutes before slicing. This resting time allows the layers to set so you get clean, beautiful slices instead of a soupy mess.
Perfect Pairings for Your Lasagna
This hearty lasagna pairs wonderfully with lighter sides that balance the richness of the cheese and provide textural contrast.
Crisp Green Salad: A simple mixed greens salad with balsamic vinaigrette cuts through the richness of the lasagna and adds a refreshing crunch that cleanses your palate between bites. The acidity from the vinaigrette helps balance the creamy cheese.
Garlic Bread: Classic for a reason, crusty garlic bread rolls are perfect for soaking up any extra marinara sauce on your plate and add that satisfying carb-on-carb comfort factor that makes Italian meals so cozy.
Roasted Vegetables: Simple roasted zucchini, bell peppers, or broccoli add nutritional balance and their caramelized edges complement the savory mushroom filling beautifully without competing for attention.
Caesar Salad: The creamy dressing and crunchy romaine provide a nice contrast to the soft, layered lasagna, while the Parmesan cheese ties the flavors together seamlessly.
Italian Grinder Salad: For something different, try this Italian grinder salad on the side. The tangy dressing and crisp vegetables provide the perfect refreshing counterpoint to the rich, cheesy lasagna.
Make-Ahead and Storage Tips
This lasagna actually tastes better the next day as the flavors have time to develop and settle together. Store leftovers in an airtight container in the refrigerator for up to 4 days. Individual portions freeze beautifully for up to 3 months.
I recommend reheating individual slices in the microwave for 2-3 minutes, or reheat the whole dish covered with foil in a 350°F oven for 20-25 minutes until heated through. Add a splash of water or extra marinara sauce before reheating to keep it moist and prevent the edges from drying out.
You can also assemble this lasagna completely up to 24 hours in advance and store it covered in the refrigerator until ready to bake. Just add an extra 5-10 minutes to the covered baking time if baking straight from the fridge. To freeze unbaked, wrap tightly in plastic wrap then aluminum foil. Bake from frozen, adding 15-20 extra minutes to the covered baking time.
FAQs
Can I use frozen spinach instead of fresh?
Yes, frozen spinach works great and is actually easier. Use 10 ounces of frozen spinach, thaw it completely, then squeeze out every drop of water you can using a clean kitchen towel or several layers of paper towels. Wet spinach will make your lasagna watery.
Do I need to cook the lasagna noodles first?
For best results with this recipe, yes. However, you can use no-boil noodles if you increase the marinara sauce to 4 cups total and make sure every noodle is completely covered with sauce so they can hydrate and cook properly during baking.
Why doesn’t this recipe include eggs in the ricotta mixture?
Many traditional lasagna recipes mix an egg into the ricotta to help it set, but I find it’s not necessary when you use good quality whole milk ricotta and let the lasagna rest properly after baking. The result is creamier and lighter without the egg.
Vegetarian Mushroom and Spinach Lasagna
Ingredients
Equipment
Method
- Preheat your oven to 375°F. Cook the lasagna noodles according to package directions until al dente (usually 8-10 minutes), then drain and lay them flat on a baking sheet drizzled with olive oil to prevent sticking.
- While noodles cook, heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the diced onion and cook for 3-4 minutes until softened and translucent. Add the minced garlic and cook for another 30 seconds until fragrant but not browned.
- Add the sliced mushrooms to the skillet and cook for 8-10 minutes, stirring occasionally, until they’ve released their moisture and the liquid has evaporated. The mushrooms should be golden brown and the pan should look fairly dry. Add the spinach in batches if using fresh, stirring until wilted (about 3-4 minutes total). If there’s excess liquid in the pan, drain it off to prevent a watery lasagna. Season with Italian seasoning, salt, and pepper. Remove from heat and set aside.
- In a 9×13-inch baking dish, spread 1 cup of marinara sauce evenly across the bottom. Layer 3 lasagna noodles over the sauce, slightly overlapping if needed depending on your noodle brand.
- Spread half of the ricotta cheese over the noodles using the back of a spoon, then top with half of the mushroom-spinach mixture, spreading it evenly. Sprinkle with 1/3 cup mozzarella and 2 tablespoons Parmesan. Pour 1 cup of marinara sauce over the cheese layer, spreading gently to cover.
- Repeat the layering process: 3 noodles, remaining ricotta, remaining mushroom-spinach mixture, 1/3 cup mozzarella, 2 tablespoons Parmesan, and 1 cup marinara sauce.
- Top with the final 3 lasagna noodles, spread the remaining marinara sauce over them completely, and finish with the remaining 1 cup mozzarella and remaining Parmesan cheese.
- Cover the baking dish tightly with aluminum foil (spray the underside with cooking spray to prevent cheese from sticking) and bake for 25 minutes. Remove the foil and bake for an additional 15-18 minutes until the cheese is golden brown and bubbly around the edges. Let the lasagna rest for 10 minutes before slicing.
