Chop and melt the chocolate using a double boiler and then pour into a mixer bowl, let cool slightly.
Slowly whisk the cream into the cooled, melted chocolate. Using an electric mixer, beat on medium speed and add the butter, splenda, cocoa powder, and extracts. Beat until smooth and fluffy.
The frosting at this point will be quite thin and easy to spread. If you wish to pipe it on in a decorative pattern, place it in the refrigerator for 20 to 30 minutes to thicken it up a bit before putting into a piping bag.