For the chocolate banana parfait, first chop the chocolate bananas. Whip the cream until stiff.
Beat the eggs with the sugar over a bain-marie until foamy, then remove from the bain-marie and continue beating so that the mixture cools down again.
Stir in whipped cream, lime juice, rum and chocolate bananas. Pour into a tureen mold (lined with plastic wrap) or small ramekins and freeze for at least 1-2 hours.
Remove the chocolate banana parfait from the mold and slice or serve in the ramekins. Garnish each with a chocolate banana.