In a very large pot, combine the oil, cauliflower, onions and olives and bring it all to a boil over medium-high heat. Cook, stirring often, for 5 minutes. (This is how it’s worded in the original book – it sounds as if the veg are boiling in oil, but really the ratio is so great that it’s a lot of cauliflower, onions and olives sort of glistening in the oil – it’s hard to tell if it’s actually “boiling”, so just make sure it’s cooking to the point where any juices you see are bubbling.)
Add the remaining ingredients and heat just until it boils. (Don't let it go on cooking too long, or the veggies will start to break down and release their liquid.) If you're using jars, pour the hot antipasto into hot, sterilized jars; seal and cool. Otherwise, remove the pot from the heat and let the antipasto cool, then transfer to containers to store in the fridge or freeze.