Ingredients:

  • 1 tablespoon olive oil
  • 1 pound mixed mushrooms (cremini, shiitake, oyster), finely diced
  • 1/2 cup finely chopped yellow onion
  • 2 cloves garlic, minced
  • 1 tablespoon fresh thyme leaves, chopped
  • 1/4 cup dry sherry or dry white wine (optional)
  • 1/4 cup heavy cream
  • 1/4 cup grated Gruyère cheese
  • Salt and freshly ground black pepper to taste
  • 1 sheet (about 14 ounces) frozen puff pastry, thawed
  • 1 large egg, beaten (for egg wash)

Instructions:

  1. Heat olive oil in a large skillet over medium heat. Add the onion and cook until softened, about 5 minutes. Add the garlic and thyme, and cook for another minute until fragrant.
  2. Add the diced mushrooms to the skillet and cook, stirring occasionally, until they release their moisture and become tender and slightly browned, about 8-10 minutes.
  3. If using, pour in the sherry or white wine and scrape up any browned bits from the bottom of the pan. Cook until the liquid is almost completely evaporated.
  4. Stir in the heavy cream and cook until the sauce thickens slightly, about 2-3 minutes. Remove from heat and stir in the Gruyère cheese. Season with salt and pepper to taste. Allow to cool slightly.
  5. Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper. Unfold the thawed puff pastry on a lightly floured surface.
  6. Spread the mushroom filling evenly over the puff pastry sheet.
  7. Using a pizza cutter or sharp knife, cut the puff pastry into approximately 2-inch squares. Transfer the squares to the prepared baking sheet, leaving a little space between each one. Brush the top of each bite with the beaten egg.
  8. Bake for 20-25 minutes, or until the puff pastry is golden brown and puffed up.
  9. Let the bites cool slightly on the baking sheet before serving.