Golden Pecan Bars

1 pkg. yellow cake mix (pudding-added version)
1/3 cup margarine or butter, softened
1 cup ground or finely chopped pecans
1 cup powdered sugar
1 teaspoon vanilla extract
4 egg whites
1/2 cup chopped pecans

Heat oven to 350 degrees. Grease 9x13-inch pan. In large bowl, combine cake mix and margarine at low speed until crumbly. Reserve 1/2 cup crumbs for topping. Press remaining crumbs in bottom of prepared pan. In same large bowl, beat ground pecans, powdered sugar, vanilla extract and egg whites on highest speed for 4 minutes. Pour evenly over crumbs. Combine 1/2 cup reserved crumbs and chopped pecans, and sprinkle over egg white mixture. Bake at 350 degrees for 20 to 30 minutes or until light golden brown. Cool completely; cut into bars. Yields 36 bars.