Pre-heat oven to 190°C
Place cocoa and caster sugar into a bowl. Stir to mix the ingredients together.
Stir the oil into cocoa and sugar mix.
In another bowl whisk together egg and Bake Aid/Relief/Digest Easy solution.
Add the egg mixture into the cocoa mixture and stir until fully combined.
In a separate bowl stir together the flour, baking powder and a pinch of salt.
Add to the cocoa mixture and mix until a soft dough forms. If it is a bit soft put it into the fridge to chill for about 1 hour.
Put the icing sugar into a shallow bowl. Roll teaspoons of the biscuit mixture into balls, then roll into the icing sugar to coat and place on biscuit trays lined with baking paper.
Bake for 10 minutes.
Remove from oven and transfer to a wire rack to. They will firm up as they cool.
Store in an airtight container.