Put the rice, milk, sugar, and vanilla in an uncovered saucepan over medium-low heat, and cook, stirring occasionally to prevent sticking, until the rice has absorbed almost all the milk, 50 minutes. It should be runny thick, like tapioca. Remove from the heat and pluck out the vanilla bean. (You can rinse the vanilla pod and use it again or store in sugar to make vanilla sugar.) Lay a piece of plastic wrap onto the surface to prevent a skin from forming, and cool to warm room-temperature.
Whip the cream to peaks and fold as much into the rice mixture as you like. Pour into a serving bowl, wrap, and chill thoroughly. Serve with fresh raspberries or raspberry coulis. In winter try simply sprinkling with cinnamon or nutmeg.