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Spinach and Mushroom Lasagna

Featured in Satisfying Hearty Mains.

Drain spinach thoroughly, cook noodles, sauté mushrooms and onions, mix with spinach and ricotta mixture, make white sauce with roux, layer everything in 9x13 pan, bake covered 30 minutes then uncovered 10 minutes at 375°F, cool 15 minutes before serving.
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Sophia from Recipes by clare team
Updated on Tue, 30 Dec 2025 20:34:30 GMT
Spinach and Mushroom Lasagna Pin it
Spinach and Mushroom Lasagna | recipesbyclare.com

Spinach and mushroom lasagna is a sophisticated, hearty alternative to traditional red-sauce recipes. Designed as a centerpiece for vegetarian guests, this dish relies on a silky homemade béchamel (white sauce) rather than marinara to let the earthy tones of sautéed mushrooms and garlic-infused spinach take center stage. The result is a rich, multi-layered masterpiece that even the most dedicated meat-eaters will reach for. While it requires about 100 minutes of total time, much of that is the meditative layering and the final bake, making it the perfect weekend project or a reliable make-ahead holiday meal.

I first developed this recipe when my brother’s new vegetarian girlfriend joined us for Thanksgiving. I didn't want her to survive on just mashed potatoes and rolls. My neighbor Tom, a staunch "meat-and-potatoes" guy, initially scoffed at the idea of a vegetable lasagna being a "real meal." After watching him quietly clear his plate and go back for a second helping, I knew I had a winner. It’s the kind of dish that bridges the gap between different dietary preferences without anyone feeling like they’re compromising.

Master Your Ingredients

  • White Mushrooms: Eight ounces, finely chopped. These are the flavor anchors; cooking them until the pan is dry concentrates their earthiness.
  • Frozen Spinach: Sixteen ounces, thawed and wrung bone-dry. Fresh spinach works but requires significantly more volume and prep.
  • Whole Milk Ricotta: Thirty ounces for a rich, creamy texture. Avoid low-fat versions, as they tend to release more water during baking.
  • White Sauce (Béchamel): A homemade roux of butter and flour whisked with 5 cups of room-temperature milk. This is the silk that binds the layers.
  • Nutmeg: Just half a teaspoon. It is the secret ingredient that transforms white sauce from basic gravy into a classic Italian component.
  • Mozzarella: Low-moisture shredded variety is best for the cheese-pull effect without adding excess liquid.
Spinach and Mushroom Lasagna Pin it
Spinach and Mushroom Lasagna | recipesbyclare.com

Creating the Perfect Layers

The Vegetable Foundation:
Sauté onions, garlic, and mushrooms in butter. The most critical step is cooking the mushrooms until all liquid has evaporated. Stir in the bone-dry spinach and let the mixture cool completely before folding it into the ricotta and egg mixture. Adding hot vegetables to raw eggs will result in unappealing scrambled bits.
Whisking the Béchamel:
Create a roux with equal parts butter and flour, then gradually whisk in room-temperature milk. Adding milk slowly at the start prevents lumps. Once thickened, stir in parmesan and nutmeg. The sauce should be thick enough to coat the back of a spoon.
The Assembly Ritual:
Start with a thin layer of white sauce on the bottom. Layer: Noodles > Ricotta Mixture > White Sauce. Repeat this three times. Finish with a final layer of noodles, the remaining white sauce, and a generous topping of mozzarella.

One of the biggest lessons I've learned is not to rush the mushroom sauté. In my first attempt, I was impatient and left them slightly wet; the lasagna ended up swimming in a pool of grey mushroom juice. Taking those extra five minutes to let the pan get dry is the difference between a professional-looking slice and a soggy mess. Also, always grease your foil! If you don't, the beautiful cheese crust will pull right off when you uncover it.

Creative Variations

For an even deeper flavor, use a mix of cremini and shiitake mushrooms. If you want a bit of a kick, add red pepper flakes to the vegetable sauté. You can also add roasted red peppers for a pop of color or a layer of basil pesto to brighten the richness of the white sauce.

Storage and Reheating

This lasagna is a dream for meal prep. It stays fresh in the fridge for 4 days and actually tastes better on day two as the flavors meld. Reheat individual slices in the microwave for 2 minutes. You can also freeze the entire assembled (but unbaked) lasagna for up to 3 months—just thaw it in the fridge overnight before baking.

Spinach and Mushroom Lasagna Pin it
Spinach and Mushroom Lasagna | recipesbyclare.com

Spinach and mushroom lasagna is more than just a "vegetarian option"; it’s a luxurious, centerpiece-worthy dish that celebrates classic Italian flavors. Whether you're hosting a holiday dinner or just want a rewarding weekend cooking project, this recipe delivers a creamy, comforting experience that will have everyone—meat-eaters included—asking for a second slice.

Frequently Asked Questions

→ Can I use fresh spinach instead of frozen?
Yes, but you'll need a lot - about 2 pounds of fresh spinach. Sauté it until wilted, then squeeze out all the water just like you would with frozen. Frozen is easier and more consistent.
→ Can I make this ahead of time?
Absolutely! Assemble the whole thing up to 24 hours ahead and keep it covered in the fridge. Just add 10 extra minutes to the covered baking time since it's starting cold.
→ Why is my lasagna watery?
You probably didn't squeeze enough water out of the spinach. Really wring it out using a steamer basket or cheesecloth until barely any water comes out.
→ Can I freeze this lasagna?
Yes! Freeze it unbaked or baked. Wrap tightly in plastic wrap and foil. Freeze for up to 3 months. Thaw in the fridge overnight before baking or reheating.
→ What can I use instead of white sauce?
You could use a good quality jarred Alfredo sauce to save time, but homemade white sauce really makes this special and isn't hard to make.
→ Why do I need to cool it before cutting?
Lasagna needs time to set up after baking. If you cut it too soon, all the layers will slide apart and you'll have a mess. The 15-minute wait is worth it for clean slices.

Spinach Mushroom Lasagna

Creamy vegetarian lasagna with layers of spinach, mushrooms, ricotta, and white sauce. Rich, gooey, and perfect for feeding a crowd.

Prep Time
45 Minutes
Cook Time
40 Minutes
Total Time
85 Minutes

Category: Hearty Mains

Difficulty: Difficult

Cuisine: Italian

Yield: 12 Servings

Dietary: Vegetarian

Ingredients

→ For the Spinach Mushroom Filling

01 4 tbsp unsalted butter
02 ½ cup white onion or shallot, finely diced
03 6 garlic cloves, minced
04 1 tsp kosher salt plus more to taste
05 Black pepper to taste
06 8 oz white mushrooms, finely chopped
07 1 tbsp Italian seasoning
08 16 oz frozen spinach, thawed and drained

→ For the Ricotta Mixture

09 30 oz whole milk ricotta
10 ½ cup Parmigiano Reggiano, finely grated
11 2 large eggs
12 ¼ cup fresh parsley, chopped
13 8 oz low-moisture mozzarella cheese, shredded and divided

→ For the White Sauce

14 5 tbsp unsalted butter
15 5 tbsp all-purpose flour
16 5 cups whole milk, at room temperature
17 ½ cup Parmigiano Reggiano, finely grated
18 1 tsp kosher salt, or more to taste
19 Black pepper to taste
20 ½ tsp ground nutmeg

→ For Assembly

21 1 lb lasagna noodles (about 20 noodles)
22 Olive oil for drizzling
23 Non-stick cooking spray

Instructions

Step 01

Thaw your frozen spinach completely and squeeze out as much water as you can. The best way to do this is to put the spinach in a metal steamer basket and close the sides to squeeze, or use cheesecloth. This works way better than paper towels and gets rid of more moisture.

Step 02

Cook the lasagna noodles until they're al dente according to the package directions. Drain them, rinse under cold water to stop the cooking, and lay them flat on sheets of parchment paper. Drizzle a little olive oil over them so they don't stick together. This makes them easier to work with when you're assembling later.

Step 03

Melt the butter in a large nonstick skillet over medium-high heat. Add the onions, salt, and pepper and cook for 2 to 3 minutes, stirring every now and then. Toss in the garlic and cook for another minute. Add the chopped mushrooms and Italian seasoning. Keep cooking until the mushrooms shrink down and all the liquid evaporates - this takes about 7 to 10 minutes. Stir occasionally.

Step 04

Take the skillet off the heat and stir in your drained spinach. Add a little more salt and pepper to taste. Set this aside to cool down.

Step 05

In a large bowl, mix together the ricotta, Parmesan cheese, half of the shredded mozzarella, eggs, and parsley. Once your spinach and mushroom mixture has cooled, add it to the ricotta mixture and combine everything together.

Step 06

In a large heavy-bottomed saucepan, melt the butter over medium heat. Add the flour and whisk to make a roux - cook for about a minute. Slowly pour in the milk a little at a time, whisking constantly between each addition. Keep whisking as you add all the milk. Continue whisking over medium heat until the mixture comes to a boil and starts to thicken. Take it off the heat and stir in the Parmesan cheese, nutmeg, salt, and pepper.

Step 07

Turn your oven to 375 degrees. Pour about half a cup of white sauce (or enough to coat the bottom) into a 9 by 13 inch oven-safe pan.

Step 08

Add a layer of lasagna noodles on top of the sauce, tearing them as needed to fit the pan. Dollop about a third of the spinach-mushroom-ricotta mixture over the noodles and spread it in an even layer. Drizzle with half a cup of white sauce. Add another layer of noodles and repeat this process two more times.

Step 09

Put one final layer of noodles on top, pour over the last of the white sauce, and sprinkle the remaining mozzarella cheese over everything. Spray one side of a piece of aluminum foil with nonstick spray and cover the lasagna with the greased side facing down.

Step 10

Bake covered with foil for 30 minutes. Take off the foil and bake for another 10 minutes until the top is browned and bubbly. You can even broil it for a few minutes at the end for extra browning - just watch it closely so it doesn't burn.

Step 11

Let the lasagna cool for at least 15 minutes before cutting into it. This helps it set up so the slices hold together. Then dig in and enjoy your creamy, gooey lasagna.

Notes

  1. Really squeeze out all the water from the spinach or your lasagna will be watery.
  2. Using room temperature milk for the white sauce helps it incorporate smoothly and prevents lumps.
  3. Drizzling the cooked noodles with olive oil prevents them from sticking together while you work.
  4. Let the mushroom mixture cool before adding to the ricotta or the heat will scramble the eggs.
  5. The 15-minute cooling time is important - it lets the lasagna firm up so it doesn't fall apart when you cut it.
  6. This makes a huge pan and feeds a crowd. Leftovers keep in the fridge for up to 4 days.
  7. You can assemble this completely ahead of time and refrigerate for up to 24 hours before baking. Just add 10 extra minutes to the covered baking time.

Tools You'll Need

  • 9x13 inch oven-safe baking dish
  • Large nonstick skillet
  • Large heavy-bottomed saucepan
  • Large mixing bowls
  • Whisk
  • Large pot for cooking noodles
  • Parchment paper
  • Aluminum foil
  • Metal steamer basket or cheesecloth

Allergy Information

Please check ingredients for potential allergens and consult a health professional if in doubt.
  • Contains dairy (butter, ricotta, mozzarella, Parmesan, milk)
  • Contains eggs
  • Contains gluten (lasagna noodles, flour)

Nutrition Facts (Per Serving)

It is important to consider this information as approximate and not to use it as definitive health advice.
  • Calories: 554
  • Total Fat: ~
  • Total Carbohydrate: ~
  • Protein: ~