Mini Beef Wellingtons

Mini beef wellingtons are an impressive presentation and will be a huge success with the party guests. We love these little pieces with fresh rosemary and puff pastry.
Preheat the oven to 450 degrees. Heat the oil in a medium nonstick skillet over medium-high heat. Add the mushrooms and rosemary; simmer for 3 minutes or until lightly browned. Add pepper and 1/8 teaspoon sea salt. Set aside.Whisk together the egg and 1 tablespoon of water in a small bowl.Roll out 1 sheet of puff pastry into a 9-inch x 12-inch rectangle on a lightly floured work surface. Cut into 12 (3-inch) squares. Place 1 beef cube in the center of each square of dough and sprinkle with a pinch of sea salt. Sprinkle each beef cube with about 1/2 teaspoon of Bursen cheese and 1 slice of mushrooms. Brush the edges of the dough squares with the egg mixture. Fold the dough corners over the filling in the center to form a bag, pinching to seal. Place on a large baking sheet lined with parchment paper. Repeat with the remaining ingredients and brush everything with the remaining egg mixture.Bake for 9 minutes or until the dough is fluffy and golden brown. Let stand for 5 minutes.Try: Diebolt-Vallois Champagne, Nevada, Blanc de Blanc, 100% Chardonnay ($36): "This sparkling wine turns out juicy and toasty - just right with herbs and puff pastry." -- Michael Velo, sparkling food expert at Chicago's Carriage House Restaurant