Forming a Puff Pastry Crust
On a parchment paper-lined baking sheet, unfold puff pastry sheet and form a 10-in. square, using a rolling pin if necessary. With a ruler, measure 2 in. from one edge in several places and mark with toothpicks. Using the toothpicks as guides, cut a 10-in. x 2-in. rectangle with a long sharp knife or pastry wheel.
From the 10-in. x 2-in. strip, cut two 10-in. x 1/2-in. strips and two 7-in. x 1/2-in. strips. Remove and discard trimmings.
Prick the 10-in. x 8-in. pastry base all over with a fork.
Brush water 1/2 in. around edges of pastry base. Place the 10-in. x 1/2-in. and 7-in. x 1/2-in. strips along edges to form sides. Press lightly.