Preheat the oven to 200 C / Gas 6. Grease the madeleine tins.
Put the eggs and sugar into a bowl and using a hand whisk beat together thick, then add the vanilla extract. Quickly but gently fold in the flour, baking powder and apples followed by the melted butter making sure the butter doesn't settle to the bottom of the bowl. Spoon the mixture into the madeleine tins.
Bake until golden, about 10 minutes, then remove from tins and leave to cool on wire racks completely. Dust with icing sugar before serving.