Ingredients

100g/3½oz butter melted and cooled slightly, plus extra for greasing
2 eggs
100g/3½oz caster sugar
100g/3½oz plain flour, plus extra for dusting
1 lemon, juice and zest
¾ tsp baking powder

If adding chocolate and sprinkles

50g – 60g white chocolate
Various sprinkles

Method

1. Brush the madeleine tray with melted butter. Put in fridge for 30 minutes or longer. Shake in a little flour to coat; tap out any excess.

2. In a bowl, sift together the flour and baking powder.

3. In another bowl, whisk together the eggs and the sugar until frothy. Whisk in the remaining ingredients except for the flour. Gently fold in the flour and baking powder. Make sure all the flour is blended in. Leave to stand for 20 minutes.

4. While the mixture is standing heat the oven to 200C/Fan 180C/400F/Gas 6.

5. Carefully pour or spoon the rested mixture into the prepared madeleine tray. Fill to the edge of each hole.

6. Bake for 8-10 minutes, or until the mixture has risen a little in the middle and is fully cooked through. Cool in the tin for 5 minutes then transfer to a wire rack and leave to cool fully.

7. If you choose to add chocolate and sprinkles, melt the white chocolate in a bain marie and brush it over half of each madeleine. Add sprinkles immediately after each brushing, working quickly before the chocolate hardens*.

*tip – I found it worked well to have a small bowl filled with sprinkles and to hold each brushed madeleine over it angled downwards, while I used a teaspoon to add the sprinkles. This should minimize the number of coloured sugar balls or similar rolling around on your kitchen floor.

A Later addition

If, like me, you only have one madeleine baking tray here’s some advice for baking several batches one after another:

I simply doubled the ingredients above and it actually made 36 madeleines. (I also replace the lemon with vanilla extract, but that’s not really relevant here. I just thought I’d tell you anyway.)
I found that a tablespoon of mixture was just about enough to make one madeleine.
Once the tin has been brushed with melted butter and chilled in the fridge there’s no need to repeat this between batches. I simply brushed on more melted butter, but even that may not have been necessary as the batter has sufficient lubricant in it anyway.
For decorating with chocolate and sprinkles, as shown here, make sure you set out all you need before baking.
I melt chocolate over a bain marie then move the saucepan and chocolate filled bowl near to the madeleines that I will then brush with the chocolate. This way the chocolate is kept melted using the residual heat of the water.
For adding sprinkles, I now use a teaspoon and gently tap the end to dislodge a few at a time.