Make a kneading dough from all the ingredients (except jam and powdered sugar). Cut the dough into 4 parts. Roll out each part into plate-sized pieces and then cut into 8 pieces of cake, place 1 teaspoon of jam on the wide side and roll up. Makes 32 croissants (can also be filled with red jam or a nut or poppy seed filling).
Bake in the oven for about 25 minutes at 180 degrees. Let cool down a little and brush with icing sugar icing.