Hot-pack method
Wear gloves while handling hot peppers and avoid touching the face or eyes. Slice peppers and onions into rings.
Combine all ingredients. Bring to a boil and boil for 1 hour, then simmer for 1 additional hour.
Cool slightly and puree. Return to the pot and carefully bring just to a boil while stirring.
Fill hot pint jars, leaving 1/2-inch headspace. Remove air bubbles, adjust headspace, wipe rims, and apply lids.
Process in a boiling-water canner for 10 minutes at 0–1,000 ft, 15 minutes at 1,001–6,000 ft, or 20 minutes above 6,000 ft.