Cut the vanilla pod lengthwise and scrape out the pulp. Boil up the pod and pulp with milk, cream and 1 pinch of salt. Stir in rice, sugar and lemon zest. Bring to the boil again and cook over low heat for 20-30 minutes. Stir several times.
Chop the chocolate, put aside a good 1 tablespoon. Switch off the stove, remove the vanilla pod. Fold chocolate and frozen berries into the rice. Leave to swell for 10-15 minutes on the plate. Stir in lemon juice.
Fill rice pudding into glasses, let it cool down. Select fresh blueberries, wash if necessary. Spread the rest of the chocolate on the rice.