Ingredients:
- 4 cups (600g) fresh blackberries, rinsed
- 3 cups (600g) granulated sugar
- 2 tbsp (30ml) fresh lemon juice
- 1 tsp (5ml) vanilla extract
- 1/4 tsp (1.25g) ground cinnamon
Instructions:
- Place the rinsed blackberries in a heavy-bottomed pot and use a potato masher to crush the berries to your preferred consistency, ensuring no large whole berries remain.
- Place the pot over medium-high heat and bring the mashed berries to a simmer for approximately 5 minutes to release natural juices.
- Stir in the granulated sugar and lemon juice.
- Increase heat to high and stir constantly. Bring the mixture to a full rolling boil (bubbles that do not stop when stirred) and maintain for 1 to 3 minutes.
- Perform the set test by placing a small spoonful of jam on a chilled freezer plate for 30 seconds; if the surface wrinkles when pushed with a finger, it is finished.
- Remove from heat and stir in vanilla extract and cinnamon if using.
- Ladle the hot jam into sterilized jars, leaving 1/4 inch of headspace, and seal tightly.