In a large pot, heat the oil, then saute the onion and garlic, stirring frequently, until just softened (about 5 minutes).

Add the cider vinegar, molasses, ginger, soy sauce and chili flakes. Bring to a boil, then reduce heat and cook for an additional 5 minutes.

Add the peanut butter (mixture will thicken considerably). Gently cook for another minute, allowing the peanut butter to melt. Be sure to stir well.

Turn off heat and using a soup ladle, fill the jars, leaving a head space of a ½ inch. Wipe top of jars with a very clean and damp cloth.

Place metal lids in boiling water for a minute or two in order to sterilize, then cover jars and secure tightly with the rings (finger tip tight only, do not over tighten).

Place jars in water bath. The water should cover the jars. Once the water bath has hit a rolling boil, set the timer for 20 minutes to ensure the sauce is processed correctly.

Carefully remove the jars and place on a wooden cutting board (for easy transport). The gratifying pop of the lids sealing will be music to your ears – do NOT touch or move the jars in any significant way until completely cooled (about 8 hours).

Lightly press the top of the jars to ensure they have sealed properly. Store in cool dark area and these will keep for a year or more (assuming they aren’t gone long before then!).