Place gelatin in a small bowl. Pour in 1/4 cup milk. Let stand for 5 minutes.
Place the bittersweet chocolate and 1/2 cup milk in the top part of a double boiler; heat over hot water, stirring constantly. When the chocolate is melted, remove pan from heat and add cocoa powder, using a whisk to mix thoroughly.
Add the gelatin/milk mixture and sugar to the chocolate and whisk until the sugar and gelatin are dissolved; let cool for five minutes. Place cream in large bowl of electric mixer and beat on high speed. When cream is nearly smooth and thick, add vanilla extract and beat for another 30 seconds. Do not overbeat. Fold chocolate into whipped cream.
Divide mixture among 10 ramekins or other small serving dishes. Refrigerate for 30 minutes or longer.
Per serving: Calories: 255, Carbohydrate: 19 grams, Fat: 19 grams, Saturated fat: 13 grams, Protein: 1 gram, Cholesterol: 67 milligrams, Sodium: 10 milligrams, Calcium: 23 milligrams.