Boil the pudding as instructed, but with 600 ml of milk and only 2 tablespoons of sugar, let cool, stirring frequently. Set aside a few slices of banana.
Put half of the biscuits in a glass bowl, drizzle with liqueur (or coffee or cocoa). Place half of the banana slices on top, drizzle with chocolate sauce. Spread half of the pudding, then half of the cream. Layer again: ladyfingers, liqueur, bananas, chocolate sauce, pudding and cream. Cover with foil and leave to soak in the refrigerator for a few hours.
Garnish with fresh banana slices and a few dabs of chocolate sauce before serving.