Full disclosure: you can use any peppers or pepper combination you want, green pepper, red pepper, banana, cayenne, habenaro, whatever tickles your tastebuds. This recipe is flexible, just hold to the ratios of overall pepper content to vinegar/sugar/seasoning and create the heat level you like. My banana pepper plants are insane this year thus explaining the following.

Process the peppers and dump them in the pot with the onion.

Next add sugar and vinegar.

Bring to a boil and babysit this madness. It foams and bubbles like crazy so do not leave unattended. You may need to remove from heat a couple times to let the foam settle. Once it's at a boil, reduce to a simmer and let it cook down for 30 minutes.

This makes about 12 cups, will keep in the refrigerator for weeks or you can waterbath for longterm storage.