Grease a Madeleine tin. Dust with flour and remove excess flour. Melt butter and let cool slightly. Beat eggs and sugar and fold in flour and baking powder.
Pour in the melted butter and fold well. Spoon mixture into the tins and level the tops. Bake at 220 degrees C for 8-10 minutes.
Cool on wire rack and re-grease and flour tin and use up all the batter. Best served on day of making.