Methods/steps

Bring a large pot of water to a boil over high heat. Add ¼ cup of pickling salt to every gallon of water in the pot. Drop in the cauliflower florets and boil them for about 3 minutes. Drain.

In a medium nonreactive pot, combine the vinegar, sugar, onions and hot red pepper flakes. Swirl until the sugar dissolves. Bring to a boil over medium heat and boil gently for 5 minutes. Remove from the heat.

Bring 6 pint jars and their bands to a boil in a large pot of water fitted with a rack. Boil for 10 minutes. Remove the jars with tongs (the tongs dont need to be sterilized). Simmer new lids in a small pan of hot water to soften the rubberized flange. When the jars are dry but still hot, gently pack the cauliflower and the onions into the jars. Don't shove, as you want the florets to retain their shape.

Cover the vegetables with the vinegar solution, making sure the hot red pepper flakes are distributed well throughout. Allow ½ to ¾ inch of headspace above the vinegar solution. Wipe the rims, set on the lids and screw on the bands fingertip tight.

Place the jars in a pot fitted with a rack and add enough water to cover the jars by 3 inches. Bring the water to a boil over high heat. Process the cauliflower for 10 minutes. Turn off the heat and let the jars sit for a few minutes and then remove them from the water. (They'll be hot, so if you don't have a jar lifter, ladle out some of the boiling water and grab the jars using an oven mitt.) Don't leave the jars in the water to cool, or the cauliflower will overcook.

Allow the cauliflower to season in a cool, dark place for 4 weeks before using it, after which it will keep for up to a year. Refrigerate after opening.