For the biscuit, wipe the zest from one lemon. Beat 5 whites with a pinch of salt until stiff, adding sugar gradually. Without stopping whipping, add the yolks one by one, flour in small portions. Add the zest and gradually pour in the vegetable oil, without stopping to beat the dough.
Pour the finished dough onto a baking sheet lined with parchment. My size is 30 * 40cm. Smooth and bake in an oven preheated to 180 degrees. about 15 minutes. Shake with the paper from the baking sheet on the table and let cool completely.
For the cream, wipe off the zest from the second lemon. In a saucepan, combine eggs, flour and sugar. Squeeze juice from two lemons, pour into a glass (250ml) and top up with cold water. Pour the mixture into a saucepan, mix well and boil, stirring until it boils and thickens. Cool completely. Whip heavy cream until stiff. Add the custard and stir until smooth at low mixer speeds.
Cut the biscuit into strips. Lubricate each with cream and roll into a roll, gradually winding one strip after another, as shown in the video.
Place the cake on the stand. Decorate with cream on top and let it brew in the refrigerator at least overnight. The cake should be well cooled and soaked so that it is easy to cut.