Plum Butter

 Plum butter 

1 vanilla bean halved lengthwise

4 pounds plums cut into ½ inch wedges

3 cups sugar

¼ cup FRESH lemon juice

Freeze several small plates for testing butter.

Scrape seeds from vanilla bean into a 5-6 quart heavy pot. Add pod and stir in remaining ingredients. Slowly bring to boil over moderate heat (about 15 minutes), stirring frequently. Boil, uncovered, stirring frequently, until plums are tender, about 5 minutes.

Discard pod. Puree plums with liquid in batches in a food mill set over a bowl. Transfer puree to pot and simmer over low heat, stirring and scraping bottom of pan frequently, until very thick, about 1 ½ to 2 hours. (The test for doneness, drop a spoonful of plum butter on a chilled plate, then tilt; the mixture should not be runny. It should be about as thick as jam.)

Ladle Plum butter in hot sterilized jelly jars; leaving ¼ inch head space. Remove air bubbles with a plastic knife. Clean the rim with a paper towel. Place the lid and ring tightly on. Process in a water bath canner for 10 minutes. 

Let stand for 1 day for the flavors to develop.