Makes about 5 (1-pt./500-mL) jars.
Bring first 7 ingredients to a boil in a 6-qt. (6-L) stainless steel or enameled Dutch oven; reduce heat, and simmer, uncovered, 20 minutes or until fruit begins to soften. Add chile peppers and salt; simmer, stirring constantly, 25 minutes or until very thick. Stir in cilantro. Remove from heat.
Ladle hot chutney into a hot jar, leaving 1⁄2-inch (.5-cm) headspace. Remove air bubbles. Wipe jar rim. Center lid on jar. Apply band, and adjust to fingertip-tight. Place jar in boiling-water canner. Repeat until all jars are filled.
Process jars 15 minutes, adjusting for altitude. Turn off heat; remove lid, and let jars stand 5 minutes. Remove jars and cool.
* ½ to 1 tsp. (2 to 5 mL) ground red pepper may be substituted.
Other varieties of plums, such as Italian prune plums, pluots, and green damson plums work nicely in this recipe too.