In a bowl, combine flour and powdered sugar; cut in the butter until crumbly. Press onto the bottom of a lightly greased 13x9x2-inch baking pan. Bake at 350° for 15 minutes. Meanwhile, in a mixing bowl, beat the eggs, sugar, lemon juice and baking powder until well mixed. Pour over crust; sprinkle coconut evenly over top. Bake at 350° for 20-25 minutes or until golden brown. Cool on a wire rack. Cut into bars.