Line a 12-hole muffin tin with paper cases and heat the oven to 200C/180C fan/gas 6. Beat the butter and sugar together in a stand mixer, or use an electric whisk. Slowly whisk in the egg, a little at a time, along with a spoonful of the flour and the vanilla extract. Fold in the remaining flour, the baking powder and sprinkles. Divide the batter between the cases and bake for 18-20 mins until lightly golden and a skewer inserted into their centres comes out clean. Leave to cool for 5 mins in the tin, then transfer to a wire rack to cool fully.
Healthy chocolate brownies
Heat the oven to 190C/170C fan/gas 5 and line a shallow 23cm square baking tin with baking parchment. Tip the beans, cocoa, coffee granules, xylitol, vanilla, eggs and yogurt into a large bowl. Blitz using a hand blender until smooth. Or, do this in a food processor. Add the baking powder, then blitz again.