I’ve always had this impression that jam and jelly were incredibly tricky to make. I’ve never properly used pectin, and any discussion of disinfecting and sealing Ball jars provokes anxiety. And yet, I’m well versed at compotes and fruit sauces to top pancakes and French toast in the morning! And they’re not so different. The ease with which every contestant on the Great British Bake Off whips up a jam for their cakes or trifles inspires me, and I’ve wanted...