Beat the yolks of the eggs and the sugar very light; then add the flour and melted butter, and then add the warm milk. Beat all till very light. Add a half teaspoonful of baking powder, and then add the whites of the eggs, beaten to a stiff froth. Beat all till very smooth. Drop a tablespoonful at a time upon the hot griddle; turn quickly and bake on the other side, allowing about two minutes in all; place on a hot platter, butter well and spread with jelly; then roll up, dust with powdered white sugar and serve very hot.