Drenched in sugary icing, its sponge filling twisted into a long plait, the yum yum is a glorified doughnut. It’s lip-smackingly sweet, gooey enough to stick your fingers together and possibly the most heart attack-inducing snack on the high street. But I bet your mouth is watering at the very thought of one. That heavenly sensation of sinking your teeth into the fluffy centre, the crack of the syrupy glaze, the wonderful stodginess of every mouthful. Yum yums may be nothing more than fancy sticks of fried dough, but they’re devilishly delicious.