Soak gelatin in cool boiled water until the granules plump and become transparent, then drain the excess water.

Peel bananas and mash together with a dollop of sugar until creamy.

Boil the syrup of the remaining sugar and water, adding citric acid. Add gelatin to the syrup and heat the mix through just until the gelatin melts, be sure not to boil the mix. Cool, mix with the banana puree and beat up until foamy.

Put the mousse in glasses or ramekins and refrigerate until set. Before serving decorate with banana slices and whipped cream.