Mix the margarine until it is very frothy, add the sugars and keep stirring until the sugar has dissolved and everything looks whitish.
Add the eggs one by one and mix each egg well. Then gradually add the lemon juice and the sifted flour with the baking powder and stir in briefly.
Spread the dough on a baking sheet lined with baking paper and bake with hot air 175 ° C top / bottom heat for about 20 minutes, the dough must remain light and is slightly moist on the inside. It doesn`t rise very high either.
After baking, stir in the frosting and spread it on the cake.
The cake stays fresh for a few days and is always juicy.