Warm milk in a pot lukewarm. Chop the chocolate. Put 25 g aside. Melt the rest over a warm water bath.
Add milk while stirring constantly and let it cool down. Whip cream until stiff and fold into the still liquid chocolate. Cover the mousse and chill for 3-4 hours. Cut off the mousse with 2 tablespoons of cam, arrange in glasses and sprinkle with the rest of the chocolate