PREHEAT oven to 350º F. Grease 9-inch-square baking pan.
MICROWAVE 1 cup chunks in small, uncovered, microwave-safe bowl on HIGH (100%) power for 45 seconds; STIR. Chunks may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until smooth; cool to room temperature.
COMBINE flour, baking powder and salt in small bowl. Beat granulated sugar, butter and vanilla extract in medium mixer bowl until creamy. Add eggs; beat until light and fluffy. Beat in melted chocolate. Stir in flour mixture until blended. Stir in mashed raspberries. Spread into prepared baking pan.
BAKE for 25 to 30 minutes or until wooden pick inserted in center comes out slightly sticky. Cool completely in pan on wire rack.
FOR RASPBERRY MOUSSE:
CHOP remaining chunks into roughly 1/4-inch pieces. Beat cream cheese, powdered sugar, vanilla extract and food coloring, if desired, in medium mixer bowl until creamy. Fold in mashed raspberries and chopped chocolate morsels.
BEAT cream in small mixer bowl until stiff peaks form. Fold into raspberry cream cheese mixture until blended. Spread mousse over cooled brownie. Refrigerate for 1 hour. Cut into bars.