Preheat your oven to 190°C/170°fan
Wipe/brush your 12 mini madeleine tray with the butter, and a dusting of flour.
Using a warm bowl, break the egg/eggs into a large bowl, add the sugar and whisk until the mixture is very pale and thick. Beat well as there is no other raising agent.
Sift the flour into the egg/sugar mixture, then add any preferred spices, beat again until you have a nice batter.
Add the rest of the butter and any zest at this stage, then gently fold into the mix.
Fill your moulds with the batter, but don’t flatten so as to get the little puff in the middle. Place in preheated oven for 7-10 mins depending on your oven. Your madeleines are ready when the little puff is there and they are golden. Leave to cool in the moulds, then place on a wire rack . . . or for as long as you can manage! A dusting of icing sugar pretties them up ready to serve.