Cut plums in half, remove pit and chop into 8ths then cut those in half.
Place in a heavy-duty saucepan with water and sugar. Stir and bring to a boil. Lower heat and cook until fruit is soft, about 20 minutes. Remove from heat and let cool slightly.
Place in blender and carefully puree. IMPORTANT: The heat from the jam can build up pressure inside the blender and spew out. Let the mixture cool slightly then just pulse in short spurts until mixture is smooth.
Clean out saucepan and place pureed mixture back into pan. Add spices and cook over low heat for 2-3 hours or until it reaches a spreadable consistency. Stir often to prevent burning.
Place in glass jars such as a mason jar and let cool. Place lid on top and store in refrigerator. Will keep about 1 month. If frozen, will keep about 6 months.