This recipe was given to Ethel, who sold the jelly at the West Tisbury Farmer’s Market, by her friend Nancy Cabot.

Yields 9 8-ounce jars

• 5 1/2 pounds ripe beach plums
• 4 cups water
• 1.75-ounce box of regular Sure-Jell fruit pectin
• 6 1/2 cups sugar

1. Crush fully ripe berries thoroughly.

2. Add water, bring to a boil, and simmer covered for 30 minutes. Strain and measure 5 1/2 cups of juice.

3. Bring juice to boil, add Sure-Jell, and boil one minute. Add sugar and boil one minute.

4. Use hot, sterilized 8-ounce jars. Put in a hot water bath for 5 minutes.