Mushroom and Spinach Lasagna

Mushroom and Spinach Lasagna is one of those recipes that proves vegetarian cooking can be just as rich and satisfying as any meat-based dish. The combination of earthy cremini mushrooms, vibrant spinach, and three types of cheese creates layers of incredible flavor that even dedicated meat lovers appreciate. I’ve been making this version for years, and it never fails to impress at family dinners or potlucks.

The first time I made this lasagna, I was skeptical about skipping the meat. But after one bite of those tender noodles layered with savory mushrooms and creamy ricotta, I was completely won over. The secret is cooking the mushrooms long enough to develop their deep umami flavor and squeezing every drop of water from the spinach. This mushroom and spinach lasagna has become my go-to for meal prep because it actually tastes better the next day when all those flavors have had time to meld together. Whether you’re serving it for a cozy Sunday dinner or making it ahead for busy weeknights, this vegetable lasagna delivers the comfort and satisfaction you crave.

What You’ll Need for This Vegetarian Lasagna

Before you start layering your mushroom and spinach lasagna, gather all your ingredients. I always recommend using cremini mushrooms instead of white button mushrooms because they have a richer, earthier flavor that really makes this dish shine. For the spinach, frozen works perfectly and is actually more convenient than fresh since you don’t have to wash and wilt it yourself.

• 1 tablespoon olive oil
• 1 large onion, chopped
• 3 cloves garlic, minced (or 2 for milder flavor)
• 16 oz (450g) cremini mushrooms, sliced (I like slicing them about 1/4 inch thick)
• 10 oz (280g) frozen spinach, thawed and squeezed completely dry
• 1 teaspoon dried thyme
• Salt and freshly ground black pepper to taste
• 9-12 lasagna noodles, no-boil or regular (no-boil saves time and works great)
• 15 oz (425g) ricotta cheese (whole milk ricotta gives the creamiest texture)
• 1 large egg, lightly beaten
• 1 cup grated Parmesan cheese
• 2 cups shredded mozzarella cheese, divided
• 24 oz (680g) jar of marinara sauce (or use homemade if you have it)

Kitchen tip: If you want an even deeper mushroom flavor, I recommend using a mix of cremini and shiitake mushrooms. The shiitakes add an almost meaty texture that takes this lasagna to the next level.

How to Make Mushroom and Spinach Lasagna Step by Step

I prefer to have all my ingredients prepped before I start assembling because it makes the layering process so much smoother. Trust me, you don’t want to be squeezing spinach while your mushrooms are burning on the stove.

Step 1: Preheat your oven to 375°F (190°C) and lightly grease a 9×13 inch baking dish with cooking spray or a bit of olive oil. This specific pan size is important because smaller pans will overflow and larger pans create thin layers.

Step 2: Heat the olive oil in a large skillet over medium-high heat. Add the chopped onion and cook for about 5 minutes, stirring occasionally, until it becomes soft and translucent. The onion should be golden at the edges but not browned.

Step 3: Add the minced garlic to the skillet and cook for 1 minute until fragrant. Be careful not to let it burn or it will taste bitter.

Step 4: Add all the sliced mushrooms to the skillet. They’ll fill the pan completely at first but will shrink down significantly. Cook for 8-10 minutes, stirring occasionally, until the mushrooms have released their liquid and started to brown. You’ll know they’re ready when they’ve reduced by about half and have a nice golden color with some caramelized edges.

Step 5: Stir in the thawed spinach (make sure it’s squeezed bone-dry in a clean kitchen towel), dried thyme, salt, and pepper. Cook for 2-3 minutes until everything is well combined and the spinach is heated through. Remove from heat and set aside. If your finished lasagna turns out watery, it’s usually because the spinach wasn’t squeezed dry enough at this step.

Step 6: In a large mixing bowl, combine the ricotta cheese, beaten egg, and grated Parmesan cheese. Mix until smooth and well combined. The egg helps bind the cheese mixture so it doesn’t fall apart when you slice the lasagna.

Step 7: Spread a thin layer of marinara sauce (about 1/2 cup) on the bottom of your prepared baking dish. This prevents the noodles from sticking. If using regular lasagna noodles instead of no-boil, make sure they’re cooked al dente according to package directions and drained before this step.

Step 8: Arrange a layer of lasagna noodles over the sauce, slightly overlapping if needed. Spread one-third of the ricotta mixture over the noodles, followed by one-third of the mushroom and spinach mixture, and about 2/3 cup marinara sauce. Sprinkle with about 1/2 cup of mozzarella cheese.

Step 9: Repeat the layering process two more times: noodles, ricotta mixture, mushroom spinach mixture, sauce, and mozzarella. You should have three complete layers total.

Step 10: For the final top layer, place the remaining noodles, spread the rest of the marinara sauce evenly over top, and sprinkle the remaining mozzarella cheese.

Step 11: Cover the baking dish tightly with aluminum foil (spray the underside with cooking spray to prevent cheese from sticking) and bake for 30 minutes.

Step 12: Remove the foil and bake for another 15-20 minutes, until the cheese is bubbly and golden brown on top with some darker browned spots. The lasagna is done when you can see the sauce bubbling around the edges and a knife inserted in the center comes out hot.

Step 13: Remove from the oven and let the lasagna rest for at least 10-15 minutes before slicing and serving. This resting time is absolutely essential because it allows the layers to set so you get clean, beautiful slices instead of a soupy mess. The resting time is included in the total recipe time.

Perfect Pairings for Your Mushroom Lasagna

This mushroom and spinach lasagna is rich and hearty, so I like to serve it with lighter, fresher sides that balance out all that creamy cheese.

Simple Green Salad: A crisp salad with mixed greens, cherry tomatoes, and a tangy vinaigrette cuts through the richness of the lasagna and adds a refreshing element to your plate.

Garlic Bread: Warm, buttery garlic bread is perfect for soaking up any extra marinara sauce. The crunchy texture contrasts beautifully with the soft lasagna layers.

Roasted Vegetables: Roasted broccoli, zucchini, or Brussels sprouts add nutrition and a slightly charred flavor that complements the earthy mushrooms in the lasagna.

Caesar Salad: The tangy, garlicky dressing and crunchy romaine create a classic Italian-American pairing that never disappoints.

More Hearty Comfort Food Recipes to Try

This mushroom and spinach lasagna pairs beautifully with other comforting dishes that make wonderful complete meals. For a cozy dinner spread, serve it alongside warming soups like Creamy Tuscan Garlic Tortellini Soup or Tuscan Ravioli Soup, which share similar Italian flavor profiles with creamy, herb-forward bases.

When planning vegetarian-friendly gatherings, consider pairing this lasagna with lighter protein options like Crispy Parmesan Chicken with Rich Garlic Sauce for meat-eating guests, or stick with the vegetable theme by adding Crispy Roasted Cauliflower and Garlic Cauliflower Mushroom Skillet as flavorful vegetable sides that complement the earthy mushroom notes in the lasagna.

Storing and Reheating Your Lasagna

One of the best things about mushroom and spinach lasagna is how well it keeps and reheats. I actually think it tastes even better on day two when all the flavors have had time to develop. Store any leftovers in an airtight container in the refrigerator for up to 4 days.

For reheating, individual slices heat up perfectly in the microwave for about 2-3 minutes on medium power. If you’re reheating a larger portion, I recommend using a 350°F (175°C) oven for about 20-25 minutes covered with foil, then remove the foil for the last 5 minutes to crisp up the top.

This vegetarian lasagna freezes beautifully. You can freeze it unbaked or already baked, whichever works better for your schedule. Wrap it tightly in plastic wrap and then aluminum foil, and it will keep for up to 3 months. If baking from frozen, add about 30 minutes to the covered baking time and make sure the center reaches 165°F before serving.

Common Questions About Making Mushroom and Spinach Lasagna

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