Dulce de Leche

Why This Recipe Works

Dulce de leche, the glossy, coffee-colored milk jam made throughout Latin America, ranges in style and consistency. It can be a schmear for buttered toast, a milky sweetener for everything from coffee to vinaigrette, a gooey topping for pancakes, a confectioners' product used to fill pastries and cookies such as alfajores, or a base for ice cream. The easiest way to make a batch is to slowly heat sweetened condensed milk (which is essentially parcooked dulce de leche) in a water bath set in the oven or in a multicooker. In either setup, the water temperature will be high enough for sugars and proteins in the mixture to undergo caramelization and the Maillard reaction and for the proteins to denature and form a semisolid gel, but it will be low enough for the mixture to brown steadily and avoid curdling. For the oven method, we transferred the canned milk to a 13 by 9-inch baking pan so that it spread into a thin layer that was mostly submerged in the water bath and cooked as evenly as possible from top to bottom. Omitting the dash of baking soda that many recipes call for also helped prevent overcooking, since the alkaline agent raises the pH of the milk, catalyzing the browning reactions at a rate that caused the dulce de leche to easily overcook. Straining the jam ensured that it was silky smooth, and stirring in a touch of vanilla extract and salt added to its toffee-like depth and balanced the sweetness.