Step 1

Wash the plums, remove the pits, and cut into quarters. Place the plums in a medium Dutch oven (or other heavy-bottomed pot). Add the water and sugar.

Step 2

Bring the mixture to a boil over medium-high heat, stirring constantly until the sugar dissolves (this only takes a few minutes). Reduce the heat to medium-low or low, and continue to cook at a gentle boil until it reaches a jelling point of 220-225°F. This generally takes my pot about 30 minutes, but the total time will vary. Stir frequently as the fruit simmers.

Step 3

Divide the preserves between 2 sterilized 8-ounce glass jars, leaving ¼-inch of headspace at the top of each jar. Wipe the rims clean with a damp cloth, then secure the lids and bands.

Step 4

Process in a boiling water bath for 10 minutes (or 15 minutes if your altitude is above 6,000 feet). Carefully remove the jars to a towel on the counter. Let stand, undisturbed, for 12 hours at room temperature. Check the seals after 12 hours by pressing the center of the lids. If the lid gives or the center button remains popped up, store in the refrigerator for up to 1 month. Properly sealed jars will keep in a cool, dark place for up to 8 months. Refrigerate after opening.