Combine all ingredients in a heavy saucepan. Bring to a simmer over medium-high heat.

Lower heat to medium-low and cook, stirring occasionally, until the fruit breaks down. This takes about 15 minutes. Mash fruit with a potato masher or a spatula and simmer for another 10 minutes.

Using a sieve, strain mixture into a clean glass jar. Discard the fruit and let the syrup cool completely. Transfer to a bottle and store in the fridge for up to a week.