Slice the bell peppers into long strips and cut onions into half rings.
Combine all the ingredients together in a large pot. The peppers will not be covered by liquid at first, but they will eventually shrink and result in the perfect amount of marinade.
Bring it to boil and cook for about 10 minutes, until the peppers turn soft. Store in the refrigerator or can the peppers (instructions below).
Canning
Sterilize the jars and preheat the oven to 215° F. Wash the jars and lids and place them in the oven for about 15 minutes or until they are completely dry. With the help of a canning funnel, place peppers into jars, while they are still hot.
Close the lids very tightly. Flip the jars upside down and keep them standing upside down for several hours to seal the lid. Store in a cool place for up to a year.