Cut off the peel from the pineapple all around, halve the pineapple and remove the stalk, then cut into small cubes. (A pineapple cutter is more elegant, of course.) Set 8 pieces aside.
We put the remaining pieces in a saucepan and let them boil down for about 20 minutes, adding the halved vanilla pod, sugar, rum and pineapple juice.
Take out the vanilla pod, puree to a disgusting, delicious mass and let cool. Take out 2 tablespoon and set aside.
Mix and whip the cream, vanilla sugar and cream stiffener and fold in the remaining pineapple mixture.
Divide the cream mousse into two small bowls, top with the pineapple mixture that you have set aside. Then spread the pistachios over it and put the pineapple pieces on two wooden skewers and place over them.