First make the icing by stirring in lemon juice in the powdered sugar until a thick glaze forms.
In a cup combine the dry ingredients, then add the wet ingredients and stir until smooth. "Bake" in the microwave for one minute.
Drizzle over the icing and dress with lemon zest if you like.
Tipps/Notes
The flour tablespoons are just as big as the tablespoons holding liquids. Meaning, don't use heaped, but leveled spoons of flour. Don't overcook your mug cake. Better to leave it in the microwave too short than too long.
Recipe by Blueberry Vegan at https://www.blueberryvegan.com/de/zitronen-tassenkuchen/