2 1/2 cups finely chopped or ground peeled peaches
1 1/2 cups finely chopped or ground pitted plums
4 tablespoons fresh lemon juice
7 1/2 cups sugar
1/2 teaspoon butter, optional
2 pouches (3 ounces each) liquid fruit pectin
In a large nonreactive kettle, combine the finely chopped or ground peaches and plums, the lemon juice, and the sugar. Cook, stirring, over medium heat until sugar is melted. Bring to a boil that can't be stirred down. Add butter, if desired, to keep foaming down. Boil, stirring, for 1 minute. Add the fruit pectin and boil, stirring, for exactly 1 minute longer. Remove from heat and skim off the excess foam.
Using tongs, carefully remove jars from the hot water, draining well. Fill them with hot fruit mixture, leaving 1/4 inch headspace. Wipe rims clean with a dampened cloth and fit seals on tops of jars. Screw on the lids firmly. Lower the jars into the water and add more hot or boiling water so the water is 1 to 2 inches above the jars. Bring to a boil. Cover and boil gently for 10 minutes.
Makes 7 half-pints