Mix the cocoa, caster sugar and oil together. Whisk in the eggs one at a time, until fully combined.

Mix the flour, baking powder and a pinch of salt together in a separate bowl, then add to the cocoa mixture and mix until you form a soft dough. If the dough feels very soft, transfer it to the fridge and chill for 1 hr.

Heat the oven to 190C/170C fan/gas 5 and line a baking tray with baking parchment. Tip the sprinkles into a shallow dish. Form a heaped teaspoon of the dough into a ball, then roll in the sprinkles to coat – you might have to press the sprinkles on, particularly if you’ve chilled the dough. If they’re not sticking well, roll the balls of dough between your hands until the mixture warms up a little. Repeat with the remaining dough, then put, evenly spaced, on the baking tray.

Bake in the centre of the oven for 10 mins – they will crinkle as they cook. The biscuits will firm up as they cool so don’t overcook them. Transfer to a wire rack and leave to cool. Will keep for four days in a biscuit tin.