Preheat oven to 350 degrees. Cream butter and brown sugar until light and fluffy. Add flour and nuts; blend until mixture resembles crumbs. Set aside 1 cup mixture. Press remainder into 8 x 8 inch pan. Bake for 12 to 15 minutes. Let cool. Beat sugar and cream cheese until smooth. Add remaining ingredients and beat well. Spread over crust. Sprinkle reserved crumbs on top, pressing down lightly with fingers. Bake for 25 minutes, cool, and cut into bars. Store in refrigerator.