Combine all the ingredients in a saucepan over medium heat—stirring occasionally.

When the mixture begins to boil, reduce the heat and simmer, uncovered, until the juices in the pan appear to thicken a bit—about 25 to 30 minutes.

Remove the pan from the heat and allow to cool slightly.

Place the contents into a blender (or use an immersion blender) and puree.

Strain through a fine-mesh sieve into a small bowl to remove the seeds, if preferred.

Pour into a glass jar or container, cool and store in the refrigerator until ready to use. Due to the pectin content in the berries, the mixture will thicken considerably after cooling; thin with a bit of water over low heat before using, if desired.