1 cup butter, room temperature (no substitutes)
1 cup sugar
1 egg, separated
1 teaspoon vanilla
2 cups flour
1 cup pecans, chopped and divided
Cream butter and sugar until light and fluffy; stir in egg yolk, vanilla and flour, blending well. Stir in 1/2-cup chopped pecans.
Spread dough evenly in a lightly buttered 15-by-10-by-1-inch pan. Beat egg whites until frothy; brush over dough. Sprinkle remaining pecans over the egg white layer.
Bake at 350 degrees for 25 minutes or until lightly browned. Cool before cutting into bars.