How to cook
For the layer, beat the eggs and sugar well, add flour, baking powder and grated lemon rind. Spread out the mixture into a large rectangular baking dish, covered with baking paper. Bake in a moderately heated oven until ready.
To make the cream, mix all the ingredients for it in a suitable pot. Stir on a medium warm stove until the cream thickens.
Mash 1 banana and add it to the cream. Smear the baked layer with the cream and put the peeled bananas in the middle. Carefully roll it up, gradually peeling off the baking paper and then squeeze the roll with it.
Put it in the refrigerator for 2 hours, then brush the top with the remaining cream and optionally sprinkle with some walnuts.