Put the prepared currants in a saucepan and mash them lightly with a potato masher. Add the preserving sugar, stir in and let everything stand for an hour. Add the orange peel and the cinnamon stick. Bring the jam to the boil while stirring and let it simmer for 4 - 5 minutes. Remove the cinnamon stick and stir in the cassis. Pour into the prepared jars and close. The jam tastes pleasantly sweet and sour and can also be used as a cake filling.