Heat oven to 350°F. Grease bottom only of 13x9-inch pan with shortening. In medium bowl, stir brownie mix, oil, water and eggs with spoon until well blended. Spread in pan.
Bake 28 to 30 minutes or until set. DO NOT OVERBAKE. Cool completely.
In medium bowl, beat 1/2 cup butter and the cream cheese until light and fluffy. Add remaining filling ingredients; beat until smooth. Spread evenly over cooled brownies.
In small saucepan, melt frosting ingredients over low heat, stirring constantly, until smooth. Remove from heat; cool 15 minutes. Pour frosting evenly over filling; spread carefully to cover. Refrigerate 1 hour before cutting. For brownies, cut into 6 rows by 8 rows. Store in refrigerator.