I went to St. Petersburg in November of 2002 with my husband and stumbled upon a little coffee place with a slow-turning dasher massaging a smooth, dark, tar-looking substance. The counter girl channeled the velvety, hot chocolate soup into demitasse cups and handed us a tiny spoon. We weren't sure what to do next and then we saw others skimming off a taste of the mixture, a spoonful at a time. Now, without all the hard-to-get visas, borscht, and cold weather, you can enjoy it too.
Make the Orange Creme Fraiche: Combine all the ingredients in a chilled bowl and whisk until soft peaks form. Chill until ready to serve.
Make the Pudding: In a bowl whisk together the sugar and cornstarch to blend. Whisk in the cream, milk, and vanilla bean. Pour mixture into a stainless steel saucepan and bring it to a boil, whisking, until thickened, about 4 minutes.
Remove the pan from the heat and whisk in the chocolate and butter until melted. Fish out the vanilla bean and rinse it. Wrap the vanilla bean in plastic wrap and refrigerate for another use.
Pour the hot chocolate into warmed demitasse cups and serve immediately with dollops of the orange creme fraiche served on the side on demitasse spoons.