Sift flour and baking powder. Knead quickly with other ingredients, otherwise the dough will become gangrenous. Wrap in cling film and leave in the fridge for about an hour.
Form dough into a roll with 3cm diameter, cut into 1cm wide pieces.
Form croissants and place them on a greased, floured baking tray. Bake at 180° until the tips are golden.
Roll the croissants still hot in finely sieved icing sugar; then let them cool down.