Ingredients:
- 2.2 lbs (1 kg) ripe plums, such as Victoria or Damson, pitted and roughly chopped
- 3 1/2 cups (750g) granulated sugar
- 1/2 cup (120ml) water
- 2 tablespoons lemon juice (freshly squeezed)
- Optional: 1 teaspoon ground cinnamon or ginger
Instructions:
- Wash, pit, and roughly chop the plums.
- In the saucepan, combine the chopped plums, sugar, water, and lemon juice. Add optional spices if using.
- Bring the mixture to a boil over medium-high heat, stirring frequently to prevent sticking.
- Reduce the heat to medium and continue to cook, stirring occasionally, until the jam reaches the setting point (220°F/104°C on a candy thermometer or passes the wrinkle test).
- Place a small spoonful of jam on a chilled plate and return it to the freezer for 1 minute. If the surface wrinkles when pushed with your finger, it's ready.
- Once the jam reaches the setting point, remove it from the heat.
- Skim off any foam that has formed on the surface of the jam with a clean spoon.
- Carefully ladle the hot jam into the sterilized jars, leaving about ¼ inch (6mm) of headspace.
- Wipe the rims of the jars clean, then place the lids on top and tighten the bands.
- If desired, process the jars in a boiling water bath for 10 minutes for longer shelf life. If not processing, invert the jars for 5 minutes to create a seal.
- Let the jars cool completely. You should hear a pop as the jars seal. Store in a cool, dark place.