Makes 4 cups.

3 cups pitted beach plums
3 cups sugar
1 cup water

Combine all three ingredients in a large nonreactive saucepan. Bring to a rapid boil for 1 minute. Reduce heat and simmer for 40 minutes, until the fruit is soft and the liquid reduces to thin syrup. Stir occasionally and skim off any foam. Remove from heat. Cover with a tight lid and let cool. Keep in the refrigerator in an airtight container.