½ orange, finely grated zest only
¼ tsp bicarbonate of soda
80²µ/2¾´Ç³ú caster sugar
65²µ/2â…“o³ú caster sugar
15²µ/½´Ç³ú cocoa powder
15²µ/½´Ç³ú icing sugar
pinch fine sea salt
100g/3oz self-raising flour
30ml/1fl oz sunflower oil, plus extra for greasing
½ tsp vanilla extract
½ tsp vinegar, any variety
50ml/2fl oz aquafaba, shop-bought or from a tin of organic chickpeas