Preheat oven to 350° F.
In a medium mixing bowl, combine flour, salt, and powdered sugar.
Cut in butter and blend with a pastry blender or fork until it resembles coarse crumbs.
Spread in a greased 9x13 inch pan, pressing firmly.
Bake at 350° for 18-20 min. Remove from oven and set aside to cool.
In a separate mixing bowl, beat eggs well.
Add flour, sugar, and baking powder and continue beating.
Add lemon juice and mix until thoroughly incorporated.
Pour mixture over cooled crust in pan.
Bake for an additional 20-25 minutes, until center is set and top is light golden brown.
Cool slightly, then transfer to refrigerator to set and cool completely.
Remove from refrigerator and sprinkle with powdered sugar; cut into squares.