Lemon Bars

2 1/4 cups all-purpose flour, divided
1/2 cup sifted powdered sugar
1 cup butter or margarine
1/2 teaspoon baking powder
4 large eggs, lightly beaten
2 cups sugar
1/3 cup lemon juice
Powdered sugar

Combine 2 cups flour and 1/2 cup powdered sugar; cut in butter with pastry blender until mixture is crumbly. Firmly press mixture in a greased 13 x 9 x 2-inch pan. Bake at 350F for 20 to 25 minutes or until lightly browned. Combine remaining 1/4 cup flour and baking powder in a small bowl; stir well. Combine eggs, 2 cups sugar, and lemon juice in a large bowl; stir in flour mixture. Pour over prepared crust. Bake at 350F for 25 minutes or until set and lightly browned. Let cool completely in pan on a wire rack. Sprinkle with additional powdered sugar; cut into bars.