Creamy Spinach Pesto Stuffed Mushrooms With Cashew Filling

Why You’ll Love This Recipe

• Ultra-creamy, dairy-free filling made from cashews, spinach, and fresh herbs that tastes rich and indulgent.
• Golden, lightly crispy panko topping for a perfect contrast to the tender, juicy mushrooms.
• Equally great as a party appetizer, holiday side, or light main with a salad.
• Can be prepped ahead so you can simply bake right before serving.

Grocery List

• Produce: 16 large cremini or white mushrooms, baby spinach, fresh basil, fresh parsley, garlic, 1 lemon.
• Dairy (optional): Finely grated Parmesan or pecorino (only if you are not keeping it dairy-free).
• Pantry: Raw cashews, extra-virgin olive oil, panko breadcrumbs (or gluten-free panko), walnuts or pine nuts, nutritional yeast (if dairy-free), fine sea salt, black pepper, red pepper flakes.

Full Ingredients

For the Mushrooms

• 16 large cremini or white button mushrooms (about 2 lb total), stems reserved
• 2 tbsp extra-virgin olive oil
• 1/4 tsp fine sea salt
• 1/8 tsp freshly ground black pepper

For Soaking the Cashews

• 1 cup raw cashews
• Boiling water (enough to cover cashews)

For the Creamy Spinach-Pesto Cashew Filling

• Soaked and drained cashews (from above)
• 1/4 cup water, plus 1–2 tbsp more as needed for blending
• 2 cups packed baby spinach (about 2 oz)
• 1/2 cup packed fresh basil leaves
• 2 tbsp fresh parsley leaves
• 2 cloves garlic, roughly chopped
• 3 tbsp nutritional yeast or finely grated Parmesan cheese
• 2 tbsp freshly squeezed lemon juice (about 1 medium lemon)
• 3 tbsp extra-virgin olive oil
• 1/2 tsp fine sea salt, plus more to taste
• 1/4 tsp freshly ground black pepper
• Pinch red pepper flakes (optional, for gentle heat)
• 1–2 tbsp finely chopped walnuts or pine nuts
• Reserved mushroom stems, finely chopped and sautéed (see instructions)

For the Crunchy Topping

• 3 tbsp panko breadcrumbs (regular or gluten-free)
• 1 tbsp extra-virgin olive oil
• 1 tbsp finely chopped walnuts or pine nuts
• Pinch fine sea salt

To Finish and Garnish

• 1–2 tbsp finely chopped fresh parsley and/or basil
• Optional: Extra lemon wedges or a light grating of lemon zest

Step-by-Step Instructions

Step 1: Soak the Cashews and Preheat the Oven

Place the raw cashews in a heatproof bowl and cover them with boiling water. Let them soak for at least 20 minutes to soften. This helps them blend into a silky, creamy filling. While the cashews are soaking, preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.

Step 2: Prep the Mushrooms

Gently wipe each mushroom with a damp paper towel or clean cloth to remove any dirt. Twist and pull out the stems and set them aside; you will use them in the filling. Arrange the hollowed mushroom caps on the prepared baking sheet, cavity-side up. Drizzle with 2 tbsp olive oil, then sprinkle evenly with 1/4 tsp salt and 1/8 tsp black pepper. Toss or rub lightly with your hands to coat. Re-arrange the caps in a single layer, still cavity-side up, so they are ready to be stuffed.

Step 3: Sauté the Mushroom Stems

Finely chop the reserved mushroom stems. Heat a small skillet over medium heat and add a light drizzle of olive oil (about 1 tsp). Add the chopped stems and a tiny pinch of salt. Cook, stirring occasionally, for 5–7 minutes, until most of their moisture has evaporated and they turn lightly golden and fragrant. This deepens the mushroom flavor and keeps excess moisture out of the filling. Remove from the heat and let cool slightly while you make the cashew-spinach pesto cream.

Step 4: Blend the Creamy Spinach-Pesto Cashew Filling

Drain the soaked cashews and discard the soaking water. Add cashews to a high-speed blender or food processor along with 1/4 cup fresh water, baby spinach, basil, parsley, garlic, nutritional yeast or Parmesan, lemon juice, 3 tbsp olive oil, 1/2 tsp salt, 1/4 tsp black pepper, and a pinch of red pepper flakes if using. Blend until very smooth and creamy, stopping to scrape down the sides as needed. If the mixture is too thick to blend, add more water 1 tbsp at a time, just until it moves freely but still stays thick and spreadable. Taste and adjust seasoning with more salt, pepper, or lemon juice as needed.

Step 5: Combine the Filling

Transfer the cashew-spinach pesto cream to a medium mixing bowl. Stir in the sautéed mushroom stems and 1–2 tbsp finely chopped walnuts or pine nuts. The filling should be thick, lush, and able to hold a mound on a spoon. If it feels too loose, you can stir in 1–2 tbsp extra finely chopped nuts or a spoonful of panko to firm it up slightly. Taste once more and adjust seasoning; this is your last chance to fine-tune the flavor before baking.

Step 6: Stuff and Top the Mushrooms

Using a small spoon, portion the filling into each mushroom cap, pressing gently and mounding it slightly above the rim. Divide the mixture evenly; each cap should be generously stuffed. In a small bowl, combine the panko, 1 tbsp olive oil, 1 tbsp chopped nuts, and a pinch of salt. Use your fingers to rub the oil into the crumbs so they are evenly moistened. Sprinkle this mixture over the tops of the stuffed mushrooms, pressing lightly so it adheres to the creamy filling.

Step 7: Bake Until Golden and Juicy

Slide the baking sheet into the preheated 400°F (200°C) oven. Bake for 18–22 minutes, until the mushrooms are tender and releasing some juices, and the topping is golden brown and crisp. If you want a deeper color on top, you can switch to the broiler for the last 1–2 minutes, watching closely to prevent burning. Remove from the oven and let the mushrooms rest for about 5 minutes; this allows the filling to set slightly. Transfer to a serving platter, scatter with chopped parsley and/or basil, and add a little lemon zest or lemon wedges if you like. Serve warm.

Pro Tips

• Choose sturdy mushrooms. Look for large, firm cremini or button mushrooms with smooth caps. Avoid mushrooms that are very soft or have broken caps, as they may collapse when stuffed.
• Dry out the stems well. Cooking the chopped stems until most moisture evaporates prevents a watery filling and concentrates the savory mushroom flavor.
• Control filling thickness. Add water to the blender very slowly. A slightly thick, spreadable consistency is ideal for neat, mounded stuffed mushrooms.
• Do not overbake. Pull the mushrooms out when they are just tender and juicy with lightly browned tops; baking too long can make them shriveled and dry.
• Use a piping bag for precision. For extra-pretty presentation, spoon the filling into a piping bag or zip-top bag with a corner snipped off and pipe it into the caps.

Variations

• Sun-Dried Tomato Twist: Add 2–3 finely chopped oil-packed sun-dried tomatoes to the filling for a sweet-savory punch and pretty red flecks against the green pesto.
• Cheesier (Non-Vegan) Version: Replace the nutritional yeast with 1/4 cup finely grated Parmesan plus 2 tbsp softened cream cheese for an ultra-rich, tangy filling.
• Big-Portobello Main Course: Use 4–6 large portobello caps instead of small mushrooms. Pre-bake the plain caps for 8–10 minutes, then stuff, top, and bake another 12–15 minutes.

Storage & Make-Ahead

To make ahead, prepare the filling up to 24 hours in advance and keep it covered in the refrigerator. You can also clean and oil the mushroom caps ahead of time; store them in an airtight container in the fridge. Just before serving, stuff, top, and bake as directed. Leftover baked stuffed mushrooms keep well in an airtight container in the refrigerator for up to 3 days. Reheat on a baking sheet at 350°F (175°C) for 10–12 minutes, until warmed through and the topping is re-crisped. These are not ideal for freezing, as the texture of both mushrooms and cashew filling can become watery once thawed.

Nutrition (per serving)

Approximate values per serving (about 4 stuffed mushrooms): 280–320 calories, 9–11 g protein, 22–25 g fat, 12–15 g carbohydrates, 3–4 g fiber, and 350–450 mg sodium (will vary with exact salt and cheese use). Using nutritional yeast instead of Parmesan keeps the recipe dairy-free and slightly lowers saturated fat; using Parmesan increases protein and calcium but also sodium and saturated fat.