Hi Caryl,

I bet the icing they used is chocolate ganache. The ingredients are basically the same as a chocolate truffle recipe. Here is Marcel Desaulniers' recipe for Quintessential Chocolate Ganach, great name. I also included another recipe that is specifically called "Chocolate Truffle Icing". The ganache recipe is great I have made a lot of Marcel Desaulniers cakes and pretty much all of them call for this topping! Good Luck!

QUINTESSENTIAL CHOCOLATE GANACHE

12 ounces semisweet baking chocolate, coarsely chopped
4 ounces unsweetened baking chocolate, coarsely chopped
2 cups heavy cream
2 tablespoons granulated sugar

Chocolate Truffle Icing

3 oz. (3/4 stick or 6 tbsp.) unsalted butter, softened
1 pound (16 ounces) confectioners' sugar
1/2 cup plus 1 tablespoon unsweetened cocoa
5-6 tablespoons buttermilk
1 teaspoon almond extract or flavoring

Combine all ingredients well until light and fluffy, adding additional buttermilk if necessary to make the icing spreadable.