With an electric mixer, beat cream cheese until smooth. Stir in mushrooms, onion, parmesan, hot sauce & pepper. Chill and refrigerate for at least an hour.

Preheat oven to 400.

Whisk the egg in a small bowl.

On a lightly floured surface, use a rolling pin to shape 1 puff pastry sheet into a 16x10-inch rectangle.

Cut pastry in half lengthwise, then spread 1/3 of the cream cheese mixture down the center of each rectangle. Brush the edges with egg.

Fold each pastry half lengthwise over the filling and pinch the edges to seal. Cut the pastries into 8 pieces each, and place on a baking sheet coated with cooking spray.

Roll the remaining puff pastry sheet into a rectangle and cut in half lengthwise again. Set one of the rectangles aside for future use or toss it, and spread the remaining 1/3 of the cream cheese mixture down the center of the other pastry. Repeat the process of folding, sealing the edges, brushing the egg, cutting into 8 pieces, and placing on a baking sheet.

Bake until browned, around 20 minutes. Serve immediately.