PREHEAT oven to 350° F. Line 9-inch-round baking pan with foil. Lightly grease.
MICROWAVE 1 cup morsels in medium, uncovered, microwave-safe bowl on HIGH (100%) power for 1 minute; STIR. Morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring until smooth. Cool to room temperature.
BEAT butter and sugar in large mixer bowl until creamy. Add eggs; beat on high speed for 2 to 3 minutes. Beat in melted chocolate. Gradually beat in flour alternately with milk. Stir in remaining morsels. Spoon into prepared baking pan.
BAKE for 40 to 45 minutes until wooden pick inserted in center comes out slightly sticky. Cool completely in pan on wire rack.
BEAT whipping cream, powdered sugar and vanilla extract in small mixer bowl until soft peaks form.
LIFT cake from pan; remove foil. Top with Sweetened Cream.