One of the things that makes mason jars so versatile is their excellent heat tolerance. Warming milk for a bottle? Mason jars can take the heat. Out of ramekins for baking? Mason jars can handle the oven. This custard bakes right in the jar and takes 5 minutes to mix up. It's full of the vitamins and fats babies need to grow big and strong. I put cinammon on top, but you could definitely torch some sugar if you want to pass this off as a healthy creme brulee-esque dessert among adults.