Scrape out seeds of vanilla bean and whisk into milk (or stir in paste) into a medium saucepot. Add cardamom, sugar and tapioca and let sit 5 minutes. Bring mixture up to a boil over medium heat, stirring constantly (this should take about 12 minutes). Once simmering, keep cooking 3 minutes more, stirring constantly (in this 3 minutes, the tapioca will double in size). Remove from heat (pudding will have only thickened a little. Whisk ¼ cup of mixture into egg yolk and add yolk to pot, stirring to blend. Whip egg white until a soft peak then stir quickly but gently into to pudding. Arrange a few raspberries into bottom of each dish and ladle warm pudding over each. Cover dishes loosely with plastic wrap and chill until set, about 3 hours.