Finely chop the bell peppers and hot peppers using a sharp knife or food processor. If you’re using jalapeños or serrano peppers, wear rubber gloves and remove the ribs and seeds to control the heat level.

Squeeze out any excess liquid with a strainer or paper towels so the mixture isn’t too watery.

Place the chopped peppers in a large saucepan, then add the sugar and vinegar to the pot, stir well, and bring to a full rolling boil over high heat. Keep an eye on it—the mixture foams up quickly.

Stir in the pectin, then continue boiling for 15 minutes while stirring often. The mixture should thicken and the flavors will deepen.

Ladle the hot jelly into sterilized half pint jars, leaving 1/2 inch of headspace. Wipe the jar rims clean with a towel, place jar lids on top and secure with a screw band.

Process the jars in a boiling-water canner for 10 minutes. Remove carefully with a jar lifter and set on tea towels to cool completely. Check that all lids have sealed before storing in a cool dark place.