Step 1

Make the aguachile: On a mandoline, thinly slice the mushroom stems crosswise into rounds (reserve the mushroom caps for another use). Transfer to a bowl or deep container. Thinly slice the red onion on the mandoline and add to the bowl with the mushrooms.

Step 2

In a blender, combine the cilantro, cucumber, serrano, jalapeño, garlic, lime juice, vinegar, and salt and blend on high speed until smooth, about 30 seconds.

Step 3

Pour the marinade over the mushrooms and onion and stir to coat completely. Let sit for 5–10 minutes.

Step 4

While the mushrooms are marinating, prepare the garnishes: using a mandoline, thinly slice the cucumber into rounds. Thinly slice the red onion.

Step 5

To serve, arrange the sliced cucumber on a serving plate. Spoon the marinated mushrooms and onion on top, along with some of the marinade. Garnish with the thinly sliced red onion, cilantro, and black pepper. Serve immediately.

Step 6

Enjoy!