Put the sugar, diced margarine, egg and lemon essence in a deep bowl. Whisk into a smooth, fluffy mixture.

Sift in the flour with the baking soda - 300 g upfront - and knead the dough. Add a little more flour if needed.

Gather the dough into a ball and roll it out into a thin 0.5 cm sheet; it's easiest to do this right on the baking sheet. Bake for 15 minutes in an oven preheated to 190 °C.

Remove the finished base and immediately trim the edges, then cut it into even strips - I got 3 strips.

For the icing, combine the powdered sugar, hot water and lemon juice in a bowl until smooth. Set aside a bit of the icing in a separate bowl, add the cocoa and mix - now you have two colors, white and chocolate. Transfer to piping bags.

Spread two strips with apple jam and stack them, then cover with the third strip. Spread its top with currant jam, or simply soak it with any syrup.

Spread the icing on top and let it set slightly. Then cut into pieces - the pastries are ready. Enjoy your meal!