Preheat oven to 400 degrees F. Line a large baking sheet with parchment paper; set aside. Unfold pastry onto a lightly floured surface. Roll pastry into a 12-inch square. If desired, trim a 1/2-inch strip from one side and use to make leaf garnishes (see below). Place pastry square on prepared baking sheet. Cut in half to form 2 rectangles; separate slightly. Prick pastry rectangles all over with a fork.

In a small bowl combine the egg and water; brush pastry with the egg mixture. Fold in all edges of each rectangle about 1/4 inch, pressing lightly as you fold to form a rim. Brush folded edges with egg mixture; set pastry aside.

In a small bowl stir together sugar and ginger. Arrange apple slices over pastry, overlapping as necessary. Sprinkle with sugar mixture.

Bake for 20 to 25 minutes or until pastry is deep golden brown and crisp. Cool on baking sheet on a wire rack. When cool, transfer to a cutting board or platter. Cut crosswise into rectangles. Makes 12 servings.

Cut leaf shape cutouts from the strip of puff pastry. Brush undersides with egg mixture and attach to sides of tarts. Brush again before baking.