For the Christmas jam with mixed berries, mix the berries with fruit juice, lemon juice and preserving sugar and let stand for about 3 hours.
Bring to a boil in a large saucepan with gingerbread spice, stirring, and boil until bubbly, about 4-5 minutes.
Make a jelly test.
Stir in rum or liqueur and pour jam into prepared hot jars.
Using an eyedropper, drizzle a few drops of alcohol over the top, light and seal immediately.