Add the diluted cocoa and put the cream to thicken in a pot on the stove, stirring nonstop.
Remove the thickened cream from the stove and dissolve in it the gelatin that's been pre-soaked in the water and add 1 tsp rum.
Once the cream cools, add the beaten to snow egg whites with a pinch of salt. Distribute thus prepared cream in dessert cups or bowls. Let it gel and upon serving, invert the cream onto saucers.
Decorate with cream or to taste with others.