Peel the bananas and cut them into thick slices. Boil 300 ml water, lemon juice, sugar, fat, vanilla pulp and banana slices. Stir starch in a little cold water until smooth. Bind banana puree with it. Bring to the boil briefly, allow to cool slightly. Whisk the egg yolks and stir into the cream. Pour into prepared glasses and use up in about 5 days