Bring the tonka bean to the boil in the milk, allow to cool.
Soak gelatin. Beat eggs and sugar until frothy. Add tonka bean milk. Dissolve the gelatine and work in. Whip the cream until stiff and fold in. Chill in the refrigerator.
Note on the tonka bean:
It contains coumarin and should only be used sparingly. If it is boiled in milk, it can be reused up to 10 times. It is very hard and should be rubbed on a nutmeg grater.