Step 1

Prepare a small boiling water bath canner and 4 half pint jars.

Step 2

Chop or crush the plums, remove the pits, and combine them with the sugar and vanilla bean seeds. Stir to incorporate the sugar.

Step 3

Once the sugar is dissolved, set the pan on the stove over high heat and bring to a boil.

Step 4

Cook, stirring regularly for 15 to 25 minutes, until the fruit thickens and reduces by at least one-third.

Step 5

Taste and add lemon juice as needed.

Step 6

When the jam seems quite thick and glossy, remove it from the heat.

Step 7

Funnel the jam into the prepared jars. Wipe the rims, apply the lids and rings, and process in a boiling water bath canner for 10 minutes.

Step 8

When time is up, remove jars from the canner and set them on a folded kitchen towel to cool.

Step 9

When jars are cool enough to handle, test seals. Sealed jars are shelf stable for at least one year. Any unsealed jars should be refrigerated and used promptly.