Place chocolate, butter and corn syrup in large saucepan; cook on medium heat until chocolate is completely melted, stirring constantly. Beat 1/2 cup of the cream and the egg yolks in large bowl until well blended. Gradually stir into chocolate mixture. Cook 3 minutes, stirring constantly. Cool to room temperature.
Beat remaining 1-1/2 cups cream, sugar and vanilla in medium bowl with electric mixer on medium-high speed until soft peaks form.
Add to chocolate mixture; stir gently until well blended.