Look, I’m gonna be honest with you. I’ve made probably fifteen different lasagna recipes in my life, and this mushroom and spinach lasagna is the one I keep coming back to. Not because it’s the fanciest or the most complicated. Actually, it’s kind of the opposite. It’s just… right.
I started making this vegetarian lasagna mushroom spinach combo about two years ago when my sister went vegetarian and I needed something to bring to Christmas dinner that wouldn’t make her feel left out. And the whole family—meat eaters included—went absolutely nuts for it. My uncle literally asked if I’d hidden meat in there somewhere. Nope. Just mushrooms doing their magic thing.
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Why This Creamy Mushroom Spinach Lasagna Works
Here’s the thing about mushrooms. When you cook them right, they get this meaty, umami-rich flavor that makes you forget you’re eating a vegetarian dish. And spinach? It adds color, nutrition, and honestly doesn’t taste like much when it’s mixed with all that cheese and sauce. Which is perfect for people like my husband who claim they don’t like vegetables. (He ate three pieces. Case closed.)
This easy mushroom spinach lasagna has layers of tender noodles, a super creamy ricotta and spinach mixture, tons of melty mozzarella, and the best white sauce I’ve ever made. Some people do red sauce, and that’s fine I guess, but the white sauce—béchamel, if you want to be fancy about it—just tastes better with the mushrooms. Trust me on this one.
My First Lasagna Disaster
Can we talk about the first time I tried making homemade mushroom and spinach lasagna? Because it was BAD. I used those regular lasagna noodles that you’re supposed to boil first, right? But I was in a hurry (shocking, I know), so I thought, “How important can boiling them really be?”
Very important. Turns out.
The noodles came out crunchy. Like, actually crunchy. My kids refused to eat it, and my dog wouldn’t even touch the piece that “accidentally” fell on the floor. That dog eats literally everything. So yeah. Now I either boil the noodles properly OR—and this is life-changing—I use no-boil lasagna noodles. Game changer.
Ingredients for This Spinach Mushroom Lasagna Recipe
Okay, so here’s what you need for this best mushroom spinach lasagna recipe. It looks like a lot, but most of it is stuff you probably have already:
For the Mushroom Filling:
- 2 tablespoons olive oil
- 1 pound baby bella mushrooms, sliced (or white button mushrooms, whatever’s on sale)
- 3 cloves garlic, minced (I use like 5 because I’m obsessed with garlic)
- Salt and pepper to taste
For the Ricotta Mixture:
- 15 oz ricotta cheese (full fat, please, we’re not on a diet here)
- 10 oz frozen spinach, thawed and squeezed dry (or 2 cups fresh, wilted)
- 1 egg
- 1/2 cup grated Parmesan
- 1/2 teaspoon nutmeg (sounds weird but trust me)
- Salt and pepper
For the White Sauce:
- 3 tablespoons butter
- 3 tablespoons flour
- 2 cups milk (I use whole milk)
- Pinch of nutmeg
- Salt and pepper
Everything Else:
- 9-12 lasagna noodles (no-boil or regular, your choice)
- 2 cups shredded mozzarella
- Extra Parmesan for the top
Shopping tip: Don’t buy pre-sliced mushrooms. They’re always kind of slimy and weird. Get whole ones and slice them yourself. Takes like two extra minutes and the texture is SO much better. Also, that frozen spinach? You HAVE to squeeze all the water out. Like, really squeeze it. I use a clean kitchen towel and wring it out like I’m angry at it. Otherwise your lasagna will be watery and sad.
How to Make This No-Boil Mushroom Spinach Lasagna
Step 1: Cook Those Mushrooms
Preheat your oven to 375°F. Wait, actually do that first. I always forget and then I’m standing there with assembled lasagna and a cold oven. Learn from my mistakes.
Heat the olive oil in a large skillet over medium-high heat. Add your sliced mushrooms and—this is important—DON’T crowd them. If your pan is too small, do them in batches. Crowded mushrooms steam instead of browning, and steamed mushrooms are sad and watery.
Cook them for like 8-10 minutes, stirring occasionally, until they’re golden brown and all their water has evaporated. They’ll shrink down to like half their size. That’s normal. Add the garlic in the last minute of cooking. Season with salt and pepper. Set aside.
Step 2: Make the Ricotta Spinach Mixture
In a medium bowl, mix together the ricotta, squeezed-dry spinach, egg, Parmesan, nutmeg, salt, and pepper. Stir until it’s all combined. It should look kinda green and lumpy and weird. That’s exactly what you want.
Fun fact: The first time I made this, I forgot the egg. The lasagna still came out okay, but the ricotta layer was a little loose. The egg helps bind everything together, so don’t skip it like I did.
Step 3: Make the Béchamel Sauce (Fancy Name for White Sauce)
This is where people get nervous, but honestly it’s super easy. Melt the butter in a medium saucepan over medium heat. Add the flour and whisk it together. It’ll make a paste—that’s called a roux, if you want to impress people at dinner parties.
Cook that paste for like a minute, whisking constantly. Then SLOWLY add the milk, whisking the whole time. It’ll be lumpy at first and you’ll panic and think you ruined it (I did), but keep whisking and it’ll smooth out. Once all the milk is in, keep cooking and whisking until it thickens enough to coat the back of a spoon. Takes maybe 5 minutes.
Season with nutmeg, salt, and pepper. Taste it. Adjust. Done.
Step 4: Assemble Your Ricotta Spinach Mushroom Lasagna
Okay, here we go. Grab a 9×13 inch baking dish. Spray it with cooking spray or rub it with butter. Nobody likes stuck lasagna.
Start with about 1/2 cup of the white sauce on the bottom of the pan. Spread it around. Then add a layer of noodles. If you’re using no-boil noodles (which I recommend), just lay them straight in. If you boiled regular noodles, lay them out.
Next, spread half of the ricotta mixture over the noodles. Then add half of the cooked mushrooms. Sprinkle with some mozzarella. Drizzle with more white sauce.
Repeat: noodles, ricotta mixture, mushrooms, mozzarella, white sauce.
Final layer: noodles, remaining white sauce, remaining mozzarella, and a good handful of Parmesan on top.
Step 5: Bake This Make-Ahead Spinach Mushroom Lasagna
Cover the whole thing with foil. Not just any foil though—spray the underside with cooking spray first, otherwise all that beautiful cheese will stick to it and rip off when you remove it. (Learned that one the hard way.)
Bake covered for 35 minutes. Then remove the foil and bake for another 15-20 minutes until the top is golden and bubbly and gorgeous.
Here’s the HARDEST part: Let it rest for at least 15 minutes before cutting into it. I know. I KNOW. You’re hungry and it smells amazing and you want to eat it RIGHT NOW. But if you cut it too soon, it’ll be a soupy mess. Let it set up. Go set the table or pour some wine or scroll through Instagram. Whatever. Just wait.
Tips for the Best Vegetarian Lasagna Mushroom Spinach
Use no-boil noodles. Seriously, they work great and save you so much time and effort. Just make sure your sauce is a little on the thinner side because the noodles absorb liquid as they bake.
Squeeze that spinach. I already said this but I’m saying it again because it’s THAT important. Wet spinach = watery lasagna. Nobody wants that.
Make it ahead. You can assemble this whole spinach mushroom lasagna white sauce masterpiece, cover it, and stick it in the fridge for up to 24 hours before baking. Just add like 10 extra minutes to the baking time since it’s cold. Perfect for entertaining or meal prep.
Freeze it. This is also a freezer-friendly mushroom spinach lasagna. Assemble it in a disposable aluminum pan, wrap it really well in plastic wrap and then foil, and freeze for up to 3 months. Bake from frozen (covered) at 375°F for about an hour, then uncovered for 20 minutes.
Mix up your mushrooms. I usually use baby bella (cremini) mushrooms, but you could use shiitake, portobello, or even a mix. Just avoid those canned mushrooms. They’re gross and we deserve better.
Why This Healthy Spinach Mushroom Lasagna Is Perfect for Weeknights
Okay, so maybe “weeknight” is pushing it a little. This isn’t a 20-minute meal or anything. But here’s the thing—you can make it on Sunday, keep it in the fridge, and bake it on Wednesday when you don’t feel like cooking. THAT’S the weeknight magic.
Also, it’s packed with vegetables (mushrooms and spinach count, right?), it’s filling, and it reheats beautifully. I’ve literally eaten leftover slices for breakfast. Don’t judge me.
My kids request this all the time now, which is hilarious because they used to act like vegetables were poisonous. Now they’ll eat an entire serving of this creamy white mushroom lasagna and not even realize they just consumed a pound of mushrooms and a bunch of spinach. Parenting win.
Serving This Easy Weeknight Mushroom Lasagna
Cut this into 8-12 servings depending on how hungry everyone is. Serve it with a simple green salad and some garlic bread. Or just eat it by itself. That’s what I usually do.
Leftovers keep in the fridge for up to 4 days, and they honestly taste even better the next day after all the flavors have melded together. Just reheat individual slices in the microwave or the whole thing in the oven.
Pro tip: If you’re reheating in the oven, cover it with foil so the top doesn’t get too brown. Heat at 350°F for about 20 minutes or until heated through.
Final Thoughts on This Mushroom and Spinach Lasagna
If you’re looking for a vegetarian comfort food lasagna that doesn’t taste “healthy” or “boring,” this is it. It’s creamy, cheesy, full of flavor, and surprisingly easy once you get the hang of it.
I’ve brought this low-calorie spinach mushroom lasagna (okay, it’s not THAT low-calorie with all that cheese, but it’s lower than the meat version?) to potlucks, family dinners, and just made it on random Tuesdays because I was craving comfort food. It never disappoints.
So yeah. Make it. Let it rest before cutting (I’M SERIOUS ABOUT THIS). And then enjoy the fact that you just made restaurant-quality lasagna in your own kitchen.
Let me know how yours turns out! Seriously, I love hearing about other people’s lasagna adventures.
Happy cooking! 🍄🧀
