Drain a can of chickpeas over a sieve and catch the remaining liquid which is called aquafaba.
Poor 90 g of it into a mixing bowl together with the salt and citric acid.
Whip the mixture on the highest speed setting of your stand mixer (KS10) for one minute.
Mix on high speed for the next two minutes, gradually adding the sugar.
Mix on high speed for another five minutes until all the sugars dissolve and the aquafaba becomes stiff.
In a separate bowl, sift together the flour, cornstarch and baking powder.
Fold the sifted ingredients into the aquafaba using a silicone spatula until no dry flour remains.
Fill the batter into a piping bag and cut a 2 cm wide hole.
Preheat the oven to 200°C, top and bottom heat.
Bake for 10 minutes then reduce the heat to 100°C and bake for another 10 minutes with an oven mitt between the door.