Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch pan.
In a medium bowl, stir together 2 cups flour and confectioners' sugar. Blend in the melted butter. Press into the bottom of the prepared pan.
Bake in the preheated oven for 15 minutes, or until golden. In a large bowl, beat eggs until light. Combine the sugar, baking powder and 1/4 cup of flour so there will be no flour lumps. Stir the sugar mixture into the eggs. Finally, stir in the lemon juice. Pour over the prepared crust and return to the oven.
Bake for an additional 30 minutes or until bars are set. Allow to cool completely before cutting into bars.