Step 1 Heat the oven to 425 degrees. On a floured surface, roll the puff pastry out to a rectangle about 10 by 20 inches; the dough will be just over one-eighth-inch thick.
Step 2 To make the base of the tart, cut a rectangle out of the rolled dough measuring 6 by 16 inches and place on a parchment-lined baking sheet. To make the borders, cut 2 strips each measuring 1 by 16 inches, then cut 2 more strips, each measuring 1 by 4 inches.
Step 3Prick the base of the tart with a fork, and brush with the beaten egg. Place the borders on top of the base, lining them up with the edges of the base. Prick the borders with a fork, and brush with the beaten egg. Place the baking sheet in the refrigerator for 20 minutes to chill the dough before baking.
Step 4Remove the sheet from the refrigerator and place in the oven. Bake the shell until it is puffed and golden brown, 25 to 30 minutes. Remove and cool the baking sheet on a cooling rack.