1. Preheat oven to 200 degrees conventional oven (190 fan). You will need a medium-sized madeleine tray.

2. In a saucepan, melt butter over a low heat. Set aside to cool to room temperature.

3. In a large bowl, mix together the flour and sugar until fully combined.

4. Using an electric whisk, mix in each egg simultaneously with a third of the cooled, melted butter, continue in turns until fully combined. Mix on a high speed (getting as much air in as possible) until it is the consistency of a pale, thick batter.

5. Stir the lime zest through the mixture.

6. Transfer the batter into a piping bag (alternatively place in a bowl, tightly covered with clingfilm). Refrigerate for four hours, if possible.

7. Grease metal madeleine trays by brushing the inside of the cavities well with melted butter. Wait 15 minutes, then lightly dust with flour (silicone bakeware will not require greasing).

8. When ready to bake, pipe as much batter as required to fill the moulds to three-quarters full (allow room for the mixture to spread, doubling in size). Once piped, refrigerate for 15 minutes.

9. Bake on the upper shelf of the preheated oven for about 12 minutes or until the cakes are golden blond and the centre has risen (the actual baking time depends on size of the moulds, so miniature cakes will bake in seven minutes).

10. Once baked, remove from the oven and immediately pop madeleines out of the moulds. After the first batch, wash the tray and bake more.

11. Either serve immediately with a dusting of icing sugar, or allow to cool, dip them in melted white chocolate and set aside until the chocolate hardens.