How-to Make a Caramel Custard
Place sugar in a heavy saucepan over medium-low; heat the sugar until melted, about 10 minutes. Do not stir. When sugar is melted, reduce heat to low. Cook, stirring constantly, with a metal spoon, until syrup is golden, about 5 minutes.
Immediately pour into an ungreased 2-qt. round baking dish, tilting pan to evenly distribute caramelized sugar over the bottom of the pan. Let stand for 10 minutes.
Prepare custard as directed in recipe. Pour over caramelized sugar. Place dish in a baking pan and add boiling water to pan to a depth of 1 in. Bake and unmold as recipe directs.