For the apple mug cake, cream together the yogurt, sugar, grated vanilla and eggs. Add the oil, then mix in both flours and the baking powder, as well as the cinnamon and cardamom.
Peel the apples and cut them into small pieces. Mix with the freshly squeezed lemon juice. Mix the apple pieces to the dough and pour into a tart pan lined with baking paper.
Bake for one hour at 160 °C. Test with chopsticks.