Heat oven to 350°F. Line cookie sheet with cooking parchment paper.
To make egg wash, in small bowl, beat egg with splash water until well blended. Set aside.
Unroll pie crusts. Spread lemon curd on 1 of the crusts, leaving 1/2-inch border around edge. Place second crust on top.
With 3-inch cookie cutter, cut out cookies by gently pressing down through both crust layers.
With handle of knife, press edges to seal; cut “x” in center of each cookie pie. Brush each cookie with egg wash; sprinkle with sugar. Place on cookie sheet.
Bake 12 to 15 minutes or until light golden brown. Cool completely, about 30 minutes, before serving.