While the crust is baking, with an electric mixer, combine the eggs, lemon juice, and zest until smooth. Add the granulated sugar, flour, baking powder, and salt, and beat until smooth. Pour the mixture over the baked crust. Bake for 25 minutes more. Remove the pan from the oven and let it cool completely. Sprinkle the top with confectioners’ sugar. Cut into squares and serve.