Heat oven to 350 degrees F. Grease 13 x 9 x 2-inch baking pan.
Beat together butter and sugar in medium-size bowl until light and fluffy, about 2 minutes. Beat in 1 egg and 1/2 teaspoon vanilla until well blended.
On low speed, beat in sifted flour and the l/8 teaspoon salt in 3 additions, beating well after each addition. Pat dough evenly over bottom of the prepared pan.
Bake in 350 degree F oven about 15 minutes or until crust is light golden.
Meanwhile, lightly beat 2 eggs in a clean medium-size bowl. Stir in brown sugar until dissolved. Stir in the pecans, 2 tablespoons flour, baking powder, 1/2 teaspoon salt and 1 teaspoon vanilla until mixed. Spread evenly over crust.
Bake in 350 degree F oven 20 minutes or until the top is golden brown. Transfer pan to wire rack and let cool completely. Cut into 2 x 2-inch diamond shapes or 2 x 1-inch bars. Makes 3 to 4 dozen.