For the berry jam with chocolate, mix the frozen berries with preserving sugar and vanilla sugar in a large pot and refrigerate for 2 hours.
Then simmer the berries for about 10 minutes, add grated milk chocolate and simmer for another 5 minutes.
Puree with a blender. Heat the prepared glasses in the oven at 150 degrees. Pour the berry jam into the jars while they are still hot and close them immediately.