1/2 package Pepperidge Farm frozen puff pastry sheet, 1 sheet
1 egg, beaten
1 tablespoon water
4 pieces baker's semi-sweet chocolate
2 tablespoons milk
1 tablespoon butter
1/2 cup chopped walnuts

Thaw pastry sheet at room temperature 30 minutes. Heat oven to 375 degrees. Mix egg and water in small bowl. Microwave chocolate, milk and butter in large bowl on HIGH 1 1/2 to 2 minutes, or until chocolate is almost melted, stirring halfway through heating time. Stir until chocolate is completely melted. 
Unfold pastry sheet on lightly floured surface. Roll into 16 X 12 rectangle. Spread chocolate mixture evenly on pastry to within 1 1/2 edges. Sprinkle walnuts over chocolate. Starting at short side, roll up jelly-roll style. Place seam side down on un-greased cookie sheet. Tuck ends under to seal. Brush with egg
mixture. Bake 35 minutes or until golden. Cool 30 minutes on cookie sheet or wire rack. Sprinkle with powdered sugar, if desired. Slice and serve warm.