Step 1

Put olive oil and onions in a large, heavy bottomed saucepan. Cook over medium-high heat stirring only occasionally; cook until golden, about 10-15 minutes.

Step 2

Add sugar and balsamic vinegar and cook until thickened and somewhat syrup-y. Add salt, pepper, and herbs.

Step 3

Cool then transfer to an airtight container. Store in the refrigerator for up to a week.

Step 4

Cool jam and transfer to a freezer safe container. Be sure to leave sufficient headspace for expansion. Freeze for up to 6 months.

Step 5

Test pH. (See notes.)

Step 6

Ladle hot jam into sterilized half pint jars, leaving about ½” headspace. Wipe rims clean and place prepared lids and rings on finger tight.

Step 7

Process in a water bath canner at a rolling boil for 15 minutes.

Step 8

After processing, carefully remove jars and allow to cool undisturbed for 24 hours. Check for seal and store in pantry for up to a year; refrigerate after opening.