Step 1

Wash and trim the stems if they've gotten hard. Quarter the figs and set them in a low, wide, non-reactive pan.

Step 2

Add the sugar to the figs and stir to combine. Let the figs and sugar macerate for several hours, until there is a goodly amount of liquid in the pan.

Step 3

When you're ready to cook, prepare a boiling water bath canner and five half pint jars.

Step 4

Add the apple cider vinegar, mustard seeds, salt, and cayenne to the pan and stir to combine.

Step 5

Set the pan over high heat and bring the fruit to a boil. Reduce the heat to medium and cook, stirring occasionally, until the fruit softens and the liquid thickens. Towards the end, you will need to stir even more.

Step 6

Once you're happy with the consistency of the mostarda (it should be softer than a jam), remove the pan from the heat.

Step 7

Funnel the mostarda into the prepared jars. Wipe the rims, apply the lids and rings, and process in a boiling water bath canner for 15 minutes.

Step 8

When the time is up, remove the jars and set them on a folded kitchen towel to cool. When the jars have cooled enough that you can comfortable handle them, check the seals. Sealed jars can be stored at room temperature for up to a year. Any unsealed jars should be refrigerated and used promptly.