1. In a heavy saucepan combine the cream, salt, sugar, vanilla and coffee. Heat over medium until bubbles form around the rim of the cream.
2. Take the pot off the heat and whisk in the chocolates until the cream is smooth. Pour into ramekins or demitasse cups. Cool to room temperature, then cover and refrigerate.
3. Serve close to room temperature, topped with dollops of cream.
Many well-known chefs work with food scientist Harold McGee, author of Keys to Good Cooking: A Guide to Making the Best of Foods and Recipes. McGee explains why thawing small cuts of meat in 100-degree water is perfectly safe.