Place chocolate in bowl of stand mixer. Pour heavy cream in a glass measuring cup and microwave 1 minute or just until it begins to boil. Slowly pour hot cream over chocolate and stir to melt. Allow mixture to cool down to room temperature. This should take at least an hour.

Stir corn syrup and butter into cooled chocolate mixture. Add half of the confectioner's sugar and beat for 1 minute. Add remaining sugar and beat on high for 3-5 minutes. At this point, your mixture should fluff up and lighten. If it does not, which happens often, place the whole bowl in the freezer for about 10-15 minutes. Return the cold bowl to the mixer stand and beat. Beat in vanilla and any additional flavoring you feel it might need.