Cook 2 tablespoons cream, white chocolate, corn syrup, and butter in a heavy saucepan over low heat, stirring until smooth. Cool.
Beat remaining whipping cream, powdered sugar, and vanilla at high speed with an electric mixer until stiff peaks form; fold into white chocolate mixture.
This mousse is out of this world. It was fairly easy to make and tasted wonderful. I used it as a filling between a double chocolate layer cake. My mouth is watering just thinking about it.
