Preheat oven to 350°. In large mixer bowl, combine all ingredients except nuts and frosting; mix until well blended. Beat on high speed 3 minutes. Stir in nuts. Pour into well greased and floured 15 x 10 inch baking pan. Bake 45 minutes or until wooden pick inserted near center comes out clean. Cool completely. Frost with cream cheese frosting. Cut into bars. Store covered in refrigerator.

Cream Cheese Frosting: In large mixer bowl, combine powdered sugar, cream cheese, butter, orange rind and vanilla, beat until smooth. Chill if desired. Makes about 2 cups.