½ (17.3-ounce) package frozen puff pastry (1 sheet)
½ cup shredded Gruyère cheese
1 large egg
1 tablespoon water
Instructions
In a medium nonstick skillet, combine butter and oil over medium-high heat. When butter melts, add mushrooms, shallots, Worcestershire sauce, rosemary, salt, and pepper. Reduce heat to medium-low, and cook, stirring occasionally, until mushrooms are browned and tender. Let cool completely.
Transfer mushroom mixture to a cutting board, and using a chef’s knife, finely chop.
Let puff pastry thaw just enough to be able to roll up and encase filling. (It should still be cold and firm.) Unroll puff pastry sheet on a lightly floured surface. Using a rolling pin, roll out puff pastry to a 12×10-inch rectangle. Spread mushroom mixture onto puff pastry, leaving a 1-inch margin around edges. Sprinkle evenly with cheese. Starting at a long end, roll up pastry firmly and evenly to encase ingredients and form a cylinder. Tuck ends under. Wrap securely in plastic wrap, and refrigerate for 1 hour and up to a day.
Preheat oven to 400°. Line a rimmed baking sheet with parchment paper.
Unwrap puff pastry cylinder. Using a serrated bread knife in a gentle sawing motion, cut 16 (¾-inch) slices from puff pastry cylinder. Place slices 2 inches apart on prepared baking sheet.
In a small bowl, whisk together egg and 1 tablespoon water. Brush slices with egg wash.
Bake until golden brown, 13 to 15 minutes. Serve immediately.
Recipe by TeaTime Magazine at https://teatimemagazine.com/mushroom-gruyere-swirls/