Wash cherries, drain well, remove the stalks and seeds and grind in a blender. Wash apricot, remove the core and cut into small pieces. Mix the sour cherries, apricots and jam sugar in a large pot. Let it cool down. Bring it to boil while stirring constantly. Let it cook at a rapid boil for 6-8 minutes. Make the “Gelierprobe”. Remove the pot from the hot stove and refine the jam with liqueur. Fill into jars and seal them immediately.