Cut the vanilla bean in half lengthwise, scrape out the seeds, add both to the milk, bring to a boil and allow to cool slightly. Remove the vanilla bean, rinse with water, dry and keep stored in sugar for another use.
Beat the egg yolks and sugar, above a hot water bath until creamy, and slowly pour in the slightly cooled vanilla milk, beating constantly until the mixture is thickened.
Allow to cool while stirring, stir in the mascarpone and chill in the refrigerator. To serve, spoon into dessert glasses and decorate with raspberries and mint leaves.