A kitchen blowtorch can brown one area of food, without heating the rest of the food, or the physical vessel the food is in or on. The classic home use is for caramelizing the top on crème brûlée.
A great way to serve leftover Christmas cake as a whole new dessert. You can make these the day before or in the morning.
If you really want to impress your friends, tell them this is crème anglaise brûlée. It’s really just custard with hardened, melted sugar on top.