This is a white lasagna — no tomato sauce — built on a cashew béchamel, sautéed cremini mushrooms, and wilted spinach, layered with no-boil noodles and baked until set. It takes real time to put together, which is exactly why it pays off across multiple meals. Make it once on a Sunday and you’re sorted for most of the week.
What makes this version work
Two things actually matter here. First, the mushrooms need to be properly browned before they go into the lasagna — not steamed, not softened, but seared. That means a hot, dry pan and leaving them alone for a few minutes before stirring. Crowding the pan drops the temperature and they’ll release water instead of browning; cook them in two batches if needed. Second, the cashew béchamel has to be thin enough to soak into the no-boil noodles as it bakes. If it’s too thick going in, the noodles stay stiff and the layers separate when you cut it. It should pour easily off a spoon — closer to heavy cream than to a paste. Both of these steps are quick to get right and hard to fix after assembly, so they’re worth slowing down for.
About the ingredients
- Nutritional yeast: Sold in the bulk or natural foods section of most grocery stores. Brands vary in saltiness — taste your béchamel before adding extra salt if you’re switching brands.
- Raw cashews: They need to be raw, not roasted or salted. Roasted cashews make the sauce taste like trail mix. Soak them in cold water for at least 4 hours, or cover with boiling water and soak for 30 minutes if you’re short on time.
- No-boil lasagna noodles: Most major brands work fine. Oven-ready rice-based noodles also work if you need a gluten-free version — just check that your béchamel is on the thinner side, since rice noodles absorb liquid faster.
- Cremini mushrooms: Baby bellas or creminis are the right call here. White button mushrooms are blander and release more water. If you want to use a mix, dried porcini rehydrated in warm water adds a deeper flavor — use the soaking liquid in the béchamel in place of some of the water.
If something goes sideways
- Béchamel seized up in the blender: Add warm water a tablespoon at a time and blend again. Cold water can make it grainy. Target a consistency that moves like a loose cream sauce.
- Noodles still firm after baking: The layers were probably too dry. Cover the dish tightly with foil and return it to the oven with two tablespoons of water drizzled around the edges. Another 10–15 minutes usually finishes them.
- Lasagna is watery when you cut it: The spinach wasn’t squeezed dry enough, or the mushrooms weren’t fully browned. Let the baked lasagna rest uncovered for at least 15 minutes — it firms up significantly as it cools and the liquid redistributes.
- Top layer is dry or cracked: The final béchamel layer was too thin or the foil came off too early. Cover for the first 35 minutes of baking, then uncover only for the last 10 to get color on top. Skip the garnish — not worth the extra dish.
- Béchamel tastes flat: It needs more salt or more nutritional yeast, almost always both. Add a small squeeze of lemon juice too — it sharpens the savory flavor without tasting citrusy.
Leftovers and meal prep
This lasagna holds up better than most after the first day. Once cooled, slice it into portions and store in airtight containers in the fridge for up to 5 days — the layers actually firm up overnight and individual slices reheat cleanly. For reheating, a covered skillet over medium-low with a splash of water works faster and keeps the noodles from drying out compared to the microwave, though the microwave is fine in a pinch (cover loosely, 2–3 minutes on medium power). To freeze, wrap individual slices tightly in plastic wrap and then foil; they keep for up to 2 months. Thaw overnight in the fridge before reheating — going straight from frozen to oven dries out the edges before the center is hot. Assembling the full dish unbaked and freezing it before cooking also works; add 20 extra minutes to the covered bake time and check the center with a knife before serving.
Vegan Spinach Mushroom Lasagna with Silky Cashew Béchamel
Equipment
- 9x13-inch baking dish
- Large skillet (12-inch)
- Medium saucepan
- High-speed blender
- Whisk
- Wooden spoon or spatula
- Chef's knife
- Cutting board
- Measuring cups and spoons
- Aluminum foil
Ingredients
For the Cashew Béchamel:
- 1 cup raw cashews unsalted; soak for ultra-smooth sauce
- 3 cups hot water for soaking; will be drained
- 2 ½ cups unsweetened soy milk barista or high-protein style preferred for body
- 3 tbsp extra-virgin olive oil for the roux
- 3 tbsp all-purpose flour unbleached preferred
- 2 tbsp nutritional yeast for subtle cheesy depth
- 1 tsp garlic powder
- 1 tsp onion powder
- ¼ tsp ground nutmeg freshly grated if possible
- 1 ¼ tsp kosher salt Diamond Crystal; reduce if using Morton
- ¼ tsp white pepper or use black pepper
- 1 tbsp fresh lemon juice balances richness
For the Spinach-Mushroom Filling:
- 2 tbsp extra-virgin olive oil
- 1 medium yellow onion, finely diced about 1 cup
- 1 ½ lb cremini (baby bella) mushrooms, sliced 1/4-inch choose firm, dry caps for best browning
- ¾ tsp kosher salt for the filling, plus more to taste
- ½ tsp freshly ground black pepper
- 4 cloves garlic, minced
- 1 tsp dried thyme or 2 tsp fresh (4g), chopped
- 1 tsp dried oregano or 2 tsp fresh (4g), chopped
- ¼ tsp crushed red pepper flakes optional heat
- 10 oz baby spinach, roughly chopped rinsed and well-dried
- 1 tsp lemon zest finely grated
- ¼ cup fresh flat-leaf parsley, chopped
For the Assembly:
- 1 tsp extra-virgin olive oil for greasing the baking dish
- 12 sheets no-boil lasagna noodles gluten-free if needed
- 2 cups vegan mozzarella shreds good-melting brand such as Violife or Miyoko’s
- ¼ cup vegan Parmesan, finely grated optional, for finishing
Instructions
- Quick-Soak the Cashews (parallel step): Place 1 cup raw cashews in a heatproof bowl and cover with 3 cups hot water. Soak for 20 minutes while you prep the vegetables and start the sauce. Drain before using.
- Prep the Aromatics: Finely dice the onion, slice the mushrooms 1/4-inch thick, mince the garlic, and chop the spinach and parsley. Keep ingredients grouped for efficient cooking.
- Blend the Cashew Base: Add the soaked, drained cashews and 2 1/2 cups unsweetened soy milk to a high-speed blender. Blend on high for 60–90 seconds until completely silky with no grit. Scrape down as needed.
- Make the Béchamel (stovetop): In a medium saucepan, heat 3 tbsp olive oil over medium heat until it shimmers. Whisk in 3 tbsp flour and cook 2 minutes, whisking constantly, until pale blond and smelling toasty (avoid browning). Slowly stream in the cashew-soy mixture, whisking vigorously to prevent lumps. Bring to a gentle simmer; cook 3–5 minutes until the sauce thickly coats the back of a spoon (nappe). Whisk in 2 tbsp nutritional yeast, 1 tsp garlic powder, 1 tsp onion powder, 1/4 tsp nutmeg, 1 1/4 tsp kosher salt, 1/4 tsp white pepper, and 1 tbsp lemon juice. Remove from heat and cover to keep warm. If too thick later, whisk in a splash more soy milk to loosen.
- Brown the Mushrooms: Heat 2 tbsp olive oil in a large skillet over medium-high heat until shimmering. Add onion and cook 3–4 minutes until translucent. Add mushrooms in an even layer and sprinkle with a pinch of the 3/4 tsp salt. Cook undisturbed 3–4 minutes to sear, then stir occasionally for 6–8 minutes more until the liquid evaporates and edges are deep brown. You should smell a savory, roasted aroma.
- Season the Filling: Add garlic, 1 tsp dried thyme, 1 tsp dried oregano, and 1/4 tsp red pepper flakes. Cook 1 minute until fragrant. Season with the remaining salt and 1/2 tsp black pepper.
- Wilt the Spinach and Finish: Add chopped spinach in batches, tossing until just wilted, 2–3 minutes. Remove from heat; fold in 1 tsp lemon zest and 1/4 cup chopped parsley. Taste and adjust seasoning—the flavors should be bright and savory.
- Preheat and Prep the Dish: Preheat the oven to 375°F (190°C). Grease a 9x13-inch baking dish with 1 tsp olive oil. If using no-boil noodles, proceed as directed; if using regular noodles, cook until very al dente according to package directions and pat dry.
- Assemble the First Layer: Spread about 1/2 cup béchamel over the bottom of the dish (thin, even coat). Lay 3–4 no-boil noodles to cover. Top with 1 generous cup béchamel, spreading to the edges. Spoon on half of the mushroom-spinach mixture in an even layer. Sprinkle with 1/2 cup vegan mozzarella.
- Repeat Layers: Add another layer of noodles, 1 generous cup béchamel, the remaining mushroom-spinach mixture, and 1/2 cup vegan mozzarella. Finish with a final layer of noodles, then spread the remaining béchamel on top and sprinkle with the remaining vegan mozzarella plus 1/4 cup vegan Parmesan (optional).
- Bake: Cover the dish loosely with foil (tent it so it doesn’t touch the cheese). Bake at 375°F (190°C) for 25 minutes. Remove foil and bake 15 minutes more, until bubbling at the edges and lightly golden on top.
- Rest and Serve: Let the lasagna rest 10–15 minutes before slicing. The layers will set, yielding clean, restaurant-worthy squares.
Notes
Mary’s Tips:
- Deeper Umami: Stir 1 tsp white miso or 1 tsp tamari into the béchamel off heat for extra savoriness.
- Faster Browning: Don’t crowd the mushrooms. Work in two batches if your skillet is small; moisture needs to evaporate for caramelization.
- Nut-Free Option: Swap the béchamel: use 3 cups unsweetened oat milk; make the roux as directed and whisk in 2 tbsp tahini or 1/2 cup pureed white beans for creaminess.
- Gluten-Free: Use gluten-free lasagna sheets and replace all-purpose flour with 2 tbsp cornstarch whisked into cold plant milk before adding to the pot.
- Cheese Choices: For best melt, use a quality brand (Violife, Miyoko’s). A light mist of water on top before baking helps shreds melt evenly.
- Herb Variation: Swap oregano/thyme for 1 tsp Italian seasoning, or finish with fresh basil.
- Optional Deglaze: After browning mushrooms, sizzle in 2 tbsp dry white wine; reduce until nearly dry before adding garlic and herbs.
Serving Suggestions:
- Plate Beautifully: Cut into neat squares; spoon a little warm béchamel dribble over the top. Garnish with parsley, a kiss of lemon zest, and a crack of black pepper.
- Color and Aroma Cues: Look for creamy white layers streaked with emerald spinach and bronzed cheese; aroma should be toasty, garlicky, and citrus-lifted.
- Pairings: Serve with a crisp arugula salad in lemon vinaigrette and warm garlic bread. Sip with a bright Italian red (Chianti) or a chilled herbal iced tea.
Culinary Context:
This is a plant-based nod to lasagne bianche—white lasagnas from Emilia-Romagna that spotlight béchamel and vegetables. I first served a version of this after a fall market stroll in Bologna; the mushrooms were so fragrant, they begged for a silky canvas. The vegan béchamel keeps that luxurious soul while staying wonderfully light.Optional Advanced Instructions:
- Make-Ahead: Béchamel can be made up to 3 days ahead; whisk in a splash of soy milk and warm gently to loosen. The filling holds 2 days refrigerated.
- Assemble Ahead: Build the lasagna, cover tightly, and refrigerate up to 24 hours. Bake straight from the fridge at 375°F (190°C) for about 50 minutes total (add 10 extra minutes).
- Freeze: Freeze unbaked, well wrapped, up to 2 months. Thaw overnight and bake as directed.
- Beginners: If you don’t have a high-speed blender, soak cashews longer (1–2 hours) or simmer them 15 minutes to ensure a smooth béchamel.
Timing:
- Prep Time: 35 minutes (cashew soak runs in parallel)
- Cook Time: 40 minutes (25 minutes covered + 15 minutes uncovered)
- Total Time: 75 minutes
Course & Cuisine:
- Course: Dinner, MainCourse
- Cuisine/Origin: Italian
Nutrition
FAQ
Can I assemble this lasagna the night before and bake it the next day?
Yes, and it actually bakes more evenly when assembled cold. Cover the dish tightly with foil and refrigerate for up to 24 hours. Add 10 extra minutes to the covered baking time since you’re starting from cold.
Do I have to use a high-speed blender for the cashew béchamel?
A high-speed blender gives you the smoothest result, but a standard blender works if the cashews are soaked long enough — at least 4 hours in cold water. Blend for a full 2 minutes and strain through a fine mesh sieve if you’re getting any graininess.
Can I use frozen spinach instead of fresh?
Frozen spinach works well and is often easier to manage. Thaw it completely and squeeze out as much water as possible — more than you think is necessary. Excess moisture is the main reason the finished lasagna turns watery.
How do I know when the lasagna is actually done baking?
Insert a thin knife or skewer into the center and hold it there for 5 seconds — it should come out hot to the touch, and the béchamel around the edges should be bubbling. If the top is browning too fast before the center is done, re-cover with foil and give it more time.
What to cook next
- Vegan Polenta Mushroom Bliss
- Macadamia Nut Pesto Pasta
- Mushroom Ale Pie Recipe
- Baked Ratatouille with Herb Oil