- 3 cups fresh blackberries or 3/4 pound frozen blackberries, thawed and drained
- 3 cups granulated sugar
- 1/2 teaspoon kosher salt
- Mash berries with sugar and salt in a bowl with a potato masher until berries are liquefied and sugar has dissolved. Let stand, covered and chilled, 3 days (to allow flavors to develop), stirring once a day.