1 2/3 c. (10 oz. pkg.) Hershey's vanilla milk chips
1 tbsp. butter flavor shortening
1/3 c. whipping cream
2 tbsp. butter
1 c. Hershey's semi-sweet chocolate chips
1/2 tsp. vanilla extract

Line square pan, 8 x 8 x 2 inches, with heavy duty foil. In small micro-proof bowl, combine vanilla milk chips and shortening. Microwave at high (100%) for 1 minute or just until chips are melted and smooth when stirred. Pour about half of vanilla mixture into prepared pan; set aside remaining vanilla mixture

In medium micro-proof bowl, combine whipped cream and butter. Microwave at high for 30 seconds to 1 minute, stirring every 30 seconds just until mixture begins to boil. Immediately stir in chocolate chips until completely melted; continue stirring until mixture cools and thickens slightly. Stir in vanilla extract.

Pour into prepared pan, over top of vanilla mixture. Chill 10 minutes. Microwave remaining vanilla chip mixture at high for 20 seconds or just until mixture is fluid; pour and spread evenly over chocolate layer. Before mixture firms up, cut through all layers, scoring into 1 inch squares. Cover; chill until firm. Cut with sharp knife, following score marks. Serve chilled.