Beat five egg yolks with the sugar in a mixing bowl until well creamy, stir in the eggnog. The gelatin, which was soaked in cold water for five minutes, melt a little hot water and fold into the egg foam.
Fold in exactly half a l of stiff whipped cream. Pour the mixture into a large enough bowl and let it rest in the refrigerator for six to eight hours.
To serve, scoop out dumplings with a tablespoon and dust with cocoa powder.