In a small saucepan, bring the milk and sugar to a simmer, stirring until the sugar dissolves; pour into a blender. Add the chocolate chips and both extracts; let stand for 1 minute to melt the chocolate. Blend on medium speed until the mixture is smooth, about 1 minute. With the machine running, gradually add the egg whites; blend well, just 30 seconds or so. Divide the chocolate mixture among 8 small bowls or 6-oz. ramekins. Cover and refrigerate until the mousse is set while you finish cooking and eating dinner, about 2 hours.
In a medium bowl, using an electric mixer, beat the cream to soft peaks. Top the mousse with the whipped cream and fresh mint sprigs.
The Do's and Don'ts of Cooking with Chocolate