Shortbread Crust 1/2 cup (1 stick) butter, softened 1/2 cup firmly packed light-brown sugar 1 1/2 cups all purpose flour 1 tsp grated lemon rind Lemon Filling 1 1/2 cups sugar 1/2 cup lemon juice 1/2 cup water 2 TBS cornstarch 2 eggs 2 teaspoons grated lemon zest Toppings 1/4 cup confectioners sugar 1/4 cup blueberries and/or raspberries
Heat the oven to 350 degrees. Grease a 9-inch square baking pan.With an electric mixer, beat together the butter and brown sugar until light and fluffy. Reduce the mixer speed low, add the lemon zest and flour and beat until well combined. Press evenly into the prepared pan and up the sides about a half inch. Bake until golden, remove and cool.Meanwhile mix 1 cup sugar, lemon juice, water, and cornstarch until well combined in a saucepan and heat to a boiling over medium-high heat, stirring constantly. Take care; the filling is much hotter than boiling water! Simmer and stir until the mixture thickens and set aside.In another bowl, beat the remaining 1/2 cup granulated sugar, eggs and lemon zest until thick. Slowly temper the lemon mixture into the egg mixture, beating constantly with a whisk. Pour the filling into the baked crust.Bake until set, about 15 to 20 minutes, remove and cool. When completely cooled, cut into bars and arrange on a plate. Decorate with berries and a dusting of powdered sugar.