Peel the bananas and slice into roundels. Put them in a bowl and squeeze the juice of 2 lemons.
Halve the cake horizontally, pour 1½ cups fruit juice over both the halves and let them soak. Cut them into strips and add to the bananas. Add the remaining fruit juice and mix.
Add 1 cup whipped cream and mix with a light hand. Divide the banana mixture equally between individual stemmed glasses. Spread the remaining whipped cream equally over each glass. Sprinkle 2 tbsps brown sugar over each. Caramelise the sugar slightly with a brulee torch and serve.