Adapted from Feasting at Home

MAKES 1 ROLL |  2-4 SERVINGS

Ingredients:

• 1 puff pastry, thawed in the fridge overnight. (Use cold-not at room temp)
• 1 tablespoon olive oil, or butter
• 1 oz container of Black Pearl Mushrooms, diced, stems OK
• 1/2 large onion or 1 small onion, diced
• 4 garlic cloves, roughly chopped
• 1 tablespoon chopped fresh rosemary, sage or thyme
• 1 teaspoon kosher salt
• 1/4 cup white wine or sherry wine
• 2 teaspoons balsamic vinegar
• ½ cup chopped, toasted pecans or walnuts
• ½ teaspoon pepper (to taste)
• Optional 1 teaspoon truffle oil
• ½ cup grated parmesan, pecorino, chevre or vegan cheese
• Egg wash – whisk 1 egg with 1 tbsp water or vegan eggwash using nut milk or coconut oil

Instructions:

1. Make sure your puff pastry is thawed before you start – still cold, but thawed.
2. Preheat oven to 400F
3. MAKE THE FILLING: Heat oil in an extra-large skillet or dutch oven, over medium-high heat. Add mushrooms, onions, garlic, salt, and rosemary and saute, stirring often, until mushrooms release all their liquid. (note: if using Black Pearl, these have less liquid and will require less time than crimini or button mushrooms) Turn heat down to medium, and continue sauteing until all the liquid has evaporated. Once the mushrooms are relatively dry in the pan, splash them with the sherry wine and balsamic vinegar, and again, sauté on medium heat until all the liquid has cooked off, avoiding a watery filling. Add the toasted chopped pecans, pepper and optional truffle oil. Taste, and adjust the salt to your liking. Fold in the cheese. 
4. Let the filling cool 15-20 minutes (you can also make the filling a day ahead and refrigerate).
5. FILL THE PUFF PASTRIES:  Carefully unroll the puff pastry onto a parchment-lined baking sheet.  Place the filling in a mound along the center and working quickly, roll the pastry up, and flip over,  seam side down. 
6. Brush with the egg or eggless wash.
7. Score the pastry using a razor blade or sharp knife with your choice of design – cross-hatch, herringbone, leafy vine or just simple diagonal slits.
8. Bake: Place the sheet pan on the middle rack in the oven for 35 minutes, checking at 20 mins, and rotating pan for even browning if necessary. Let the pastry bake until it is a really deep golden color – to ensure it’s done and flaky all the way through. You may need to add 5 more minutes depending on your oven. Convection will help if you have this setting (use it for the last 5-10 minutes) 
9. Cool for  5-10 minutes before cutting and serving. Garnish with Rosemary Sprigs. Serve warm.