Heat white chocolate and 3 tablespoons whipping cream in heavy small saucepan over low heat, stirring frequently, until chocolate is melted. In large bowl, beat cream cheese, powdered sugar and crème de cacao until smooth. While beating, slowly add white chocolate mixture until smooth. In chilled small bowl, beat remaining whipping cream until stiff peaks form. Fold into white chocolate mixture. Fold in miniature chocolate chips. Spread over cake. Refrigerate until firm, 1 hour or overnight.