Preheat oven to 160° C for convection oven or 175° C for a conventional oven
Prepare a cake tin by greasing it well or lining it with a piece of baking paper
Sift flour, chickpea flour, potato starch, baking powder and salt together in a bowl, and mix well with a whisk to evenly distribute all dry ingredients.
220 g all-purpose flour, 30 g lupin flour, 20 g potato starch, 12 g baking powder, 2 g salt
Melt the butter together with the lemon zest
95 g butter, 1 lemon, its zest
Mix milk, sugar, vanilla sugar and lemon juice with a hand blender in a measuring cup until the sugar dissolves.
180 g castor sugar, 1 tsp vanilla sugar, 250 ml soy milk, 30 g lemon juice
Now add the butter mixture to the milk mixture and mix with a whisk, hand blender or food processor.
Pour the liquid part onto the dry ingredients and stir well with a whisk to form a smooth batter
Pour the batter into the prepared cake tin, place the cake in the centre of the oven and bake for 50 minutes until cooked and golden brown. The cake is done when a skewer comes out clean and dry or when the core temperature is at least 80 °C.
Meanwhile, prepare the candied lemon peel and spoon some of the juice of the lemon peel over the surface of your still warm cake, about 15 minutes after it came out of the oven.
Allow the cake to cool for about 20 minutes before carefully releasing the cake and letting it cool further on a wire rack.