Plum Conserve Jam

1. Stage

Prepare jars for canning: Prepare your jars for canning. Place them in a large (12-quart) pot of water on top of a steaming rack (so they don't touch the bottom of the pan). The water should cover the tops of the jars by at least 1 inch. Cover, bring the water to a rolling boil, and boil for 10 minutes. Wash the lids in hot, soapy water.

2. Stage

Meanwhile, start cooking the conserve: Put the plums, sugar, orange, lemon, and raisins into a large 6 or 8-quart pan. Heat until boiling. Gently boil for 20 to 25 minutes, stirring frequently, or until the mixture starts to thicken slightly. If you want, use kitchen shears to cut some of the longer citrus rinds. Stir in walnuts.

3. Stage

Carefully ladle the conserve into the jars: When the conserve is ready, remove the jars from the pot of water and dump the water in the jars back into the pot. Fill the jars one at a time, leaving 1/4-inch headspace at the top of the jars for a vacuum seal. Wipe the rims clean with a clean, wet paper towel. Place the lids on the jars, securing with jar rings (do not over-tighten). Using jar lifters, lower the jars back into the pot, making sure there's enough water to cover by at least 1 inch. Bring to a rolling boil, then boil the jars for 5 minute. Remove the jars with the jar lifters and set on a clean kitchen towel. Allow the jars to sit overnight. You will hear them make a popping sound as a vacuum seal is created.