Catt's Lemon Bars

This are just so good, they are almost refreshing.

Catt's Lemon Bars

2 1/2 cups flour, separated and sifted in one 2 cup increment, and a 1/2 cup increment
1/2 cup powdered sugar
3/4 cup butter or margarine
1/2 teaspoon baking powder
4 eggs, beaten
2 cups sugar
1/3 cup lemon juice
(I use a fresh lemon, and I zest it too and add that to the mix, too. But if it is the difference between using lemon juice out of the bottle and not making the lemon bars because you don't have a fresh lemon, please...use the juice from the bottle. Just as long as you make them. )

Combine 2 cups of the flour, 1/2 cup powdered sugar and margarine and mix until blended.
Press dough into 9x 13 greased pan, bringing edges up a bit. Bake 20 minutes in a 350 degree oven until lightly browned. Combine remaining flour, baking powder, eggs, sugar, and lemon juice (and zest if you have it) until mixed well, and pour over baked crust.

Return to oven and bake until set, about 25 - 30 minutes. Let cool for about 20 minutes, then dust them lightly with additional powder sugar, if desired.