Preheat oven to 350°. In a large bowl, combine the flour, confectioners' sugar and salt. Cut in butter until crumbly. Pat into a greased 15x10x1-in. baking pan. Bake 16-20 minutes or until set and top is golden brown.
For topping, combine the eggs, sugar, lemon juice, baking powder and salt in a bowl. Pour over crust (pan will be full). Bake 16-20 minutes or until set and top is golden brown. Cool. Dust with confectioners' sugar. Cut into squares.