1. Preheat oven to 350 F. Lightly grease 9-by-9-by-2-inch baking pan.

2. Sift flour with baking powder In medium bowl, with electric mixer at medium speed, cream butter with granulated sugar and egg yolks, until light and fluffy.

3, At low speed, beat in flour mixture, along with milk and vanilla, just until combined. Turn into prepared pan, spreading evenly. Bake 20 minutes.

4. In small bowl, heat egg whites, just until stiff. Gradually beat in brown sugar, then stir in nuts. Spread evenly on top of warm crust. Bake 20 minutes longer, until puffed and lightly browned.

5. Cut into 16 bars while still warm. Let cool completely in pan on wire rack. Makes 16.