I used Mirabelle plums from the garden for this recipe but any type of plum should work with this jam recipe. A ratio of 1kg plums to 1kg sugar to 100ml water should be followed. Ingredients (for 1kg plums - see ratio above) plums. granulated sugar. 2 star anise. 2 stick cinnamon. 1 tbsp lemon juice. knob of butter. Method. Stone the plums and chop into smallish chunks. Add the plums and water to a pan and bring to a slow simmer. Cook for about 15 minutes. Wrap the star anise and cinnamon in a muslin cloth, tie and add to the plums along with the sugar and the lemon juice. Continue to simmer and stir for 15 minutes. To thicken the jam, bring to a more vigorous simmer and continue to stir for a few minutes until the jam has thickened. Remove the spices, add the butter, stir and allow to cool slightly before spooning into sterilised jam jars.