Crust
2 cups flour
1 cup butter
1/2 cup powdered sugar
Filling
1 3/4 cups sugar
1/2 cup Key lime juice
1/4 cup flour
4 eggs
1/2 tablespoon baking powder powdered sugar
Crust
Heat oven to 350°F. Line 9x13 inch baking pan with foil. Combine flour, butter and powdered sugar in food processor fitted with metal blade. Process till fine crumbs are formed or cut ingredients together using pastry blender. Pat mixture into bottom of prepared pan. Bake 20 minutes and remove from oven.
Filling
For filling, combine sugar, lime juice, flour, eggs and baking powder in same food processor. Blend till well mixed. Pour over crust. Bake till knife inserted in center comes out clean, about 20 minutes. Cool completely; sprinkle with powdered sugar.