In a bowl, combine butter, 1 cup flour, and powdered sugar and mix with a spoon. In a greased 8 x 8 x 2 square pan, pat the mixture evenly on the bottom of the pan. Bake it at 325 degrees for 20 minutes. Do not cool crust.
In a mixer, combine white sugar, eggs, 2 TBSP flour, and the lemon juice. Mix until smooth. Pour mixture over the hot crust. Bake at 325 degrees for 25 minutes. Remove from oven and let it cool.
Sprinkle some powdered sugar over the top. Refrigerate for at least 2 hours before cutting into squares.