Heat the oven to 375°F.  Beat the eggs in a medium bowl with a fork or whisk.
Stir the granulated sugar, cornstarch and coffee crystals in a 1-quart saucepan.  Add the milk and stir until the mixture is smooth.  Cook and stir over medium heat until the mixture boils and thickens.  Remove the saucepan from the heat.  Gradually stir half the milk mixture into the eggs. Return the egg mixture to the saucepan.  Cook and stir over medium heat for 1 minute.  Remove the saucepan from the heat.
Pour the water into a small cup.  Sprinkle the gelatin over the water and let stand for 1 minute.  Stir the gelatin mixture into the pastry cream.  Stir in the butter.  Place plastic wrap directly onto the surface of the pastry cream and refrigerate for 30 minutes.
Fold the whipped cream into the pastry cream.  Cover and refrigerate the cream mixture for 15 minutes or until well chilled.
Unfold the pastry sheet on a lightly floured surface.  Roll the pastry sheet into a 12-inch square.  Cut into 4 (12x3-inch) rectangles. Cut 3 rectangles into 4 squares, making 12 squares in all. Cut the remaining rectangle into 12 (2x1 1/2-inch) rectangles.  Prick the pastries with a fork.  Place the pastry squares and pastry rectangles onto 2 baking sheets.
Bake for 15 minutes or until the pastries are golden brown.  Remove the pastries from the baking sheets and let cool on wire racks for 10 minutes.
Divide the cream mixture among the pastry squares.  Top with the pastry rectangles and sprinkle with the confectioners' sugar.