Mom's Lemon Bars

When I asked if anyone had this recipe no one seem to have it. I finally found it in mom's recipe file. So for all those who would like the recipe here it is. (we think these are the best)

2 C. flour
1/2c. powder sugar
1 C. margarine or butter

Mix thoroughly and put into bottom of greased 9x13 baking pan. Bake at 350 for 20 minutes.

Mix:
2 C. sugar
7Tbsp. lemon juice
4 Tbsp. flour
pinch of salt
4 eggs

Mix sugar, juice, flour, eggs and salt. Pour over baked crust. Return to oven and bake for an additional 20 minutes. Remove from oven sprinkle with powder sugar.