In a slow cooker, combine the cranberries, strawberries, ground cinnamon, ground nutmeg, ground cloves, ground ginger, and brown sugar.
Cover the slow cooker and cook on high for 4 hours or until the fruit has softened and the mixture has thickened.
Once done, put everything into blender and combine until you get a jam-like consistency. Do not overblend as you will get more of a buttery texture and not a jam.
Transfer the Christmas jam to clean jars, seal them tightly, and refrigerate.
