Although I call this chilli jam, I don't mean by this that it's the sort of thing you'd spread on your toast at breakfast (though smeared inside a bacon sandwich, it could be a real help one hungover morning) but rather a chilli jelly — chelly? — that glows a fiery, flecked red and is fabulous with cold meats or a cheese plate. And just a small pot of it makes a gorgeous present. "Jam sugar" is a sugar that has pectin added to it and is very good for setting jams and jellies which are low in natural fruit pectin. It is easily bought in most UK supermarkets but sadly is difficult to find elsewhere. If you can’t get jam sugar then you can use granulated sugar and add a 1.75 ounce box of regular powdered fruit pectin to the sugar and vinegar at the beginning of step 2 (or use the amount of powdered pectin recommended on the packaging). Powdered fruit pectin can be bought from canning suppliers. And please read the Additional Information section at the end of the recipe before proceeding. For US cup measures, use the toggle at the top of the ingredients list.