How are they all related?
One day, after months of making hundreds of custards, it hit me: all these desserts are the same. Crème caramel is a baked custard that's cooked in a caramel-lined ramekin; crème brûlée is a baked custard that's topped with a sheer, crackly layer of caramelized sugar; and pot de crème is, well, a baked custard.
Same technique, but different results. You'll notice that all three custards share the same mixing and baking techniques. Look closer, however, and you find that the proportions for each custard vary and that, while the variations seem small, they actually correspond to a different result.
Crème brûlée is the richest of the three. All heavy cream and yolks, this custard cooks up rich and thick—a wonderful contrast to the glassy brittle layer of caramelized sugar it's topped with. Next is pot de crème. With equal parts cream and milk and lots of egg yolks, it is eggy and soft and smooth, pure custard to be spooned out of a cup and savored unadorned. And finally, crème caramel is the lightest, with whole eggs as well as yolks, milk as well as cream. It's meant to be inverted out of its baking ramekin so its tawny caramel sauce can pool around it; the egg whites make the custard firm enough to stand on its own.