For the filling: 2 tablespoons fresh lemon juice 1/2 teaspoon freshly grated lemon zest 2 large eggs, beaten lightly 1 cup sugar 2 tablespoons all-purpose flour ?½ teaspoon double-acting baking powder For the glaze: 3/4 cup confectioners sugar 1/2 teaspoon vanilla 1 tablespoon unsalted butter, softened 1 tablespoon milk Make the crust: Preheat the oven to 350 F. In a bowl whisk together the flour and the confectioners sugar, add the but ter, and blend the mixture until it resembles coarse meal. Press the mixture evenly onto the bottom of a greased 9-inch square baking pan and bake it in the middle of the oven for 15 minutes, or until it is golden. Make the filling: In a bowl whisk together the lemon juice, the zest, the eggs, the sugar, the flour, and the baking powder, whisking until the filling is combined well. Pour the filling over The prepared crust and bake the confection in the middle of the oven for 25 minutes. Let the confection cool in the pan set on a rack and chill it, covered, for least 3 hours or overnight. Make the glaze: In a bowl with an electric mixer beat together the confectioners sugar, vanilla and butter. Add the milk and beat until smooth. Transfer the glaze to a heavy-duty resealable plastic bag and cut a small opening with scissors in one corner of the bag. Drizzle the glaze over the confection in a decorative pattern, Let the confection stand until the glaze is set, and cut it into 48 squares.