Preheat
oven to 400F. Lightly butter 2 heavy large baking sheets. Roll out 1
puff pastry sheet on lightly floured surface to 16x13-inch rectangle.
Trim edges neatly, forming 15x12-inch rectangle. Cut rectangle into
twenty 3-inch squares. Using small sharp knife, make 1-inch-long
diagonal cut in all 4 corners of 1 square, cutting toward center (do
not cut through center). To form pinwheels, fold every other point of
puff pastry toward center of square, pressing to adhere. Repeat with
remaining puff pastry squares.
Brush
pinwheels lightly with egg glaze. Sprinkle each with 1/2 teaspoon
sugar. Place scant 1/2 teaspoon jam in center of each. Transfer to
prepared baking sheet. Bake until pinwheels are golden and puffed,
about 13 minutes. Using metal spatula, transfer cookies to rack and
cool. Repeat with remaining puff pastry sheet, glaze, sugar and jam.
Sprinkle
cookies with powdered sugar, if desired. (Can be prepared ahead. Place
cookies between waxed paper sheets in airtight containers and freeze up
to 2 weeks; thaw before packing, or store airtight at room temperature
up to 3 days.).