To make the crust, place the graham cracker crumbs, melted butter, sugar and zest in a bowl. Stir to combine. Pour the mixture into the prepared pie plate, and press with your fingers to create an even layer on the bottom and up the sides. (I pressed the crumbs about 1-inch up the sides of the springform pan). Use a flat-bottomed glass to facilitate pressing the crumbs along the bottom and to help with the edges. Keeping the glass flat, move toward the edges; it will press the crumbs along the sides, creating an even layer all around. Blind bake the crust for 5 to 7 minutes, or just until it starts to brown. Place on a wire rack to cool slightly.