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Spinach béchamel lasagna with portobellos, a velvety sauce, and a deeply flavored, cheesy filling makes the best cozy comfort food. Bonus: it’s also packed with veggies.
Why we love this recipe
Lasagna needs no introduction, but we especially adore this savory vegetarian version. It’s rich, creamy, and just the right amount indulgent, to be sure. But it’s also full of flavorful mushrooms and spinach. It’s:
- A true all-in-one meal (but also loves wine, salad, and crusty bread)
- Equally at home at a cozy dinner party or for several family meals throughout the week
- Great with or without marinara sauce
I first published this recipe here in the very early days of Umami Girl, back in 2009. I’ve updated the post for clarity and tweaked the recipe just a bit over time. We continue to make it regularly, and I hope you will, too.
What you’ll need
Here’s a glance at the ingredients you’ll need to make this recipe.
- Frozen spinach works beautifully in this recipe, and it’s my go-to. You can substitute fresh if you like. Either way, you’ll cook it first according to the instructions below and be absolutely sure to squeeze out as much moisture as you can before adding it to the filling.
- Portobello mushroom caps provide an umami-rich, almost meaty heft to this vegetarian lasagna. They’ll release a lot of moisture as they cook in a bit of butter and salt. As you’ll see in the video, we let the liquid simmer away before adding the other ingredients.
- I tend to keep oven-ready lasagna noodles (also called no-boil) on hand. They work very well here, and the proportions in the béchamel sauce are designed for it to be thin enough to help hydrate the noodles in the oven. That said, you can use anything you like, from pre-boiled lasagna noodles to homemade.
How to make it
Here’s what you’ll do to make a great pan of spinach béchamel lasagna with portobellos. There are a few separate elements to make, but it’s so worth it.
- First you’ll cook the chopped portobellos in some butter and salt until they release their moisture and it cooks away. Then add the onion and garlic and keep cooking until they’re tender.
- Next, make the béchamel sauce. Melt the butter, whisk in the flour until it’s foamy. Pour in the milk all at once an bring to a boil, whisking almost constantly. Cook until it’s thickened a bit, though this sauce won’t thicken quite as much as a béchamel with more standard proportions. Off the heat, stir in some of the nutmeg and parmesan, salt and pepper.
- Make the filling by beating the eggs a bit in a very large bowl, stirring in the ricotta, some of the parmesan, salt, pepper, and nutmeg. Then stir the cooked and drained spinach and cooked mushroom mixture.
- Finally, assemble the lasagna in a deep 9×13-inch baking pan. See the recipe card below for specific layering instructions. Place on a rimmed baking sheet to catch any drips and bake at 425°F, covered and then uncovered, for about 40 minutes, until it’s hot, bubbly perfection.
Expert tips and FAQs
I like to use frozen spinach in this recipe because it feels more efficient both in terms of cost and cooking process. But you can absolutely use fresh — either baby spinach or chopped mature spinach — if you prefer.
Steam or sauté it until wilted and dramatically reduced in volume. Let cool and then place in a colander and squeeze out and discard absolutely all the moisture that you can.
Sure, you can use any type or combination of mushrooms you like, as long as you chop them and cook away the moisture. Shiitakes would work beautifully and provide a slightly bolder flavor, and you could easily use half shiitakes and half creminis.
Six portobello caps weigh about 18 ounces (510 grams). Use an equivalent weight of your mushrooms of choice.
You can do all the prep for this lasagna up to about 24 hours in advance, cover it tightly with foil, and keep it in the fridge or freeze it. Bake straight from the fridge, adding a few minutes to the cooking time if necessary.
Even though this recipe has both béchamel sauce and ricotta, you can freeze it. The better option is to assemble it in the pan (consider using a disposable foil tray), let cool completely, wrap tightly with plastic wrap and then foil, and freeze before baking. (A tray of lasagna, fresh or frozen, makes a great baby, housewarming, or convalescence gift.)
Defrost in the refrigerator overnight and then bake as directed.
You can also freeze leftovers after baking, using a similar method for freezing, defrosting, and reheating. Or freeze cooked lasagna in individual portions for easy reheating.
More spinach and mushroom favorites
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Spinach Béchamel Lasagna with Portobellos
Ingredients
- 6 tablespoons (84 grams) butter, divided
- 6 large portobello mushroom caps, (510 grams)
- 1 ½ teaspoons fine sea salt, divided
- 1 large yellow onion, finely diced
- 6 cloves garlic, chopped
- 20 ounces (567 grams) frozen spinach
- 2 large eggs
- 32 ounces (900 grams) whole-milk ricotta cheese
- 6 ounces (170 grams) grated Parmigiano-Reggiano cheese, divided
- ¼ teaspoon ground nutmeg, divided
- ¼ cup (30 grams) all-purpose flour
- 5 cups 1(183 ml) whole milk
- 9 ounces (255 grams) no-boil lasagna noodles
- ½ teaspoon freshly ground black pepper
- Marinara sauce for serving, optional
Instructions
- Preheat oven to 425°F with a rack in the center.
For the Filling
- Finely chop the portobellos (into about ¼-inch dice), or roughly chop them with a knife and then pulse briefly in a food processor.
- Melt 2 tablespoons of the butter in a large non-stick skillet over medium-high heat.
- Add the portobellos and 1/2 teaspoon of the salt. Sauté until they’ve released their moisture and it has cooked off, and the mushrooms are beginning to brown.
- Add the onion and garlic and reduce the heat to medium. Sauté, stirring occasionally, until the onions and garlic have softened a bit but not browned.
- Meanwhile, cook the spinach according to package directions. Drain in a colander and let it sit until it is cool enough to handle. Pick it up by the handful and squeeze out as much liquid as you can.
- Crack the eggs into a large bowl and beat. Add the ricotta, about half of the parmesan cheese, 1/8 teaspoon nutmeg, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Mix thoroughly.
- Stir in the drained spinach until well distributed. Then stir in the portobello mixture.
For the Béchamel Sauce
- Melt the remaining 4 tablespoons butter in a medium, heavy-bottomed pot over medium heat.
- Add the flour all at once and cook, stirring constantly, for one minute.
- Add the milk, raise the heat to high, and bring to a boil, stirring almost constantly.
- When the mixture boils, reduce the heat so it is simmering vigorously and cook for ten minutes or so, stirring occasionally, until the sauce is thick enough to coat the back of your spoon.
- Turn off the heat and add about half of the remaining parmesan cheese, the remaining 1/8 teaspoon nutmeg, 1/2 teaspoon salt, and 1/4 teaspoon pepper.
To Assemble and Bake the Lasagna
- Begin with a deep 9×13-inch baking pan. It needs to be at least 2 1/2 inches deep — the shallower 2-inch depth will not accommodate all the ingredients.
- Spread a thin layer of the béchamel to coat the bottom of the pan.
- Layer 1/3 of the lasagna noodles over the sauce. Top the noodles with half of the ricotta filling mixture.
- Repeat with another layer of béchamel, noodles, and ricotta filling.
- For the last layer, put the remaining 1/3 of the noodles directly over the second layer of ricotta filling, pour the remaining béchamel on top, and sprinkle with the remaining parmesan cheese.
- Cover the pan with foil and set it over a rimmed baking sheet to catch any drips. Bake for 30 minutes.
- Remove foil and bake for an additional 10 minutes to brown the top a bit.
- Rest lasagna for 10 minutes or so before serving. It’s great alone or with marinara sauce to pass at the table.
Notes
- I like to use frozen spinach in this recipe because it feels more efficient both in terms of cost and cooking process. But you can absolutely use fresh — either baby spinach or chopped mature spinach — if you prefer. Steam or sauté it until wilted and dramatically reduced in volume. Let cool and then place in a colander and squeeze out and discard absolutely all the moisture that you can.
- Portobello mushroom caps provide an umami-rich, almost meaty heft to this vegetarian lasagna. They’ll release a lot of moisture as they cook in a bit of butter and salt. As you’ll see in the video, we let the liquid simmer away before adding the other ingredients. You can substitute any type or combination of mushrooms you like, as long as you chop them and cook away the moisture. Shiitakes would work beautifully and provide a slightly bolder flavor, and you could easily use half shiitakes and half creminis. Six portobello caps weigh about 18 ounces (510 grams). Use an equivalent weight of your mushrooms of choice.
- I tend to keep b (also called no-boil) on hand. They work very well here, and the proportions in the béchamel sauce are designed for it to be thin enough to help hydrate the noodles in the oven. That said, you can use anything you like, from pre-boiled lasagna noodles to homemade.
- You can do all the prep for this lasagna up to about 24 hours in advance, cover it tightly with foil, and keep it in the fridge or freeze it. Bake straight from the fridge, adding a few minutes to the cooking time if necessary.
- Even though this recipe has both béchamel sauce and ricotta, you can freeze it. The better option is to assemble it in the pan (consider using a disposable foil tray), let cool completely, wrap tightly with plastic wrap and then foil, and freeze before baking. (A tray of lasagna, fresh or frozen, makes a great baby, housewarming, or convalescence gift.) Defrost in the refrigerator overnight and then bake as directed. You can also freeze leftovers after baking, using a similar method for freezing, defrosting, and reheating. Or freeze cooked lasagna in individual portions for easy reheating.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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How many servings does it makes?
I made this last night for a holiday party because I knew we had some vegetarians coming….EVERYONE LOVED it!!! It was so delicious!!! I did, however, have a lot of leftover bechamel sauce but my pan was smaller than 9×12. Anyways…DELICIOUS thank you!
So happy to hear that — thanks for letting me know!