For the apricot cake, wash the lemon, grate the zest and squeeze out the juice. Preheat the oven to 180 °C top and bottom heat.
Beat soft butter with sugar and vanilla sugar until fluffy. Add the eggs. Mix flour, salt and baking soda and add to the dough together with lemon zest and juice. Line a baking tray with baking paper and coat with the batter.
Cut the apricots in half and pit them. Cover the dough with the apricot halves (cut side up) and bake the apricot cake for 25 minutes in the preheated oven until golden brown. Sprinkle with powdered sugar before serving.