1 pound large cremini mushrooms or small portobello mushrooms (stemmed, 16 ounces, about 12 mushrooms with a 2-inch diameter)
1 ¼ cups raw walnut pieces, divided
2 cloves garlic, smashed and peeled
1 Tbsp. extra-virgin olive oil
½ cup finely diced shallots (about 2 medium shallots)
2 Tbsp. finely chopped sage leaves
2 teaspoons minced fresh rosemary
¼ teaspoon dried thyme
¼ teaspoon plus ⅛ teaspoon sea salt, divided, plus more to taste
Freshly ground black pepper, to taste
⅓ cup dried cranberries, finely chopped
1 teaspoon sherry vinegar
1 Tbsp. nutritional yeast flakes (for the walnut "parmesan")
¼ cup flat-leaf parsley, stemmed and finely chopped (optional)
- Preheat oven to 400F. Line a large baking sheet with parchment paper.
- Use a small spoon to gently scrape away the gills from each mushroom.
- Add 1 cup of the walnuts and the garlic to a small food processor and pulse 15 to 20 times, or until very finely chopped or coarsely minced.
- Heat a large sauté pan over medium-low heat and add the olive oil, walnut mixture, shallots, sage, rosemary, thyme, ¼ teaspoon of the sea salt, and black pepper, and continue to cook for 5 minutes, or until the shallots soften and the walnuts are lightly toasted, stirring frequently. Remove from the heat and stir in the cranberries and sherry vinegar. Taste and season with more sea salt and black pepper, if desired.
- Prepare the walnut "parmesan" topping (if using). Add remaining ¼ cup walnuts and ⅛ teaspoon sea salt to a small food processor along with the nutritional yeast flakes. Process for 20 seconds, or until the mixture resembles finely grated parmesan cheese. Set aside.
- One at a time, pick up each mushroom and use a small spoon to fill it with warm walnut mixture. Use the back of the spoon to gently compact the mixture into the mushroom cap and transfer to the lined baking tray. Repeat, stuffing all of the mushrooms. Sprinkle the top of each mushroom with a generous pinch of the walnut "parmesan" (if using). (You'll have quite a bit of leftover parmesan that you can use to garnish before serving.)
- Bake for 16 to 20 minutes, or until the mushrooms are tender and the top of the filling is golden brown.
- If desired, garnish the mushrooms with another pinch of parmesan and sprinkle with the parsley. Serve immediately. Enjoy!