How to Make It
Preheat the oven to 425° and butter a 2-quart shallow baking dish. In a large bowl, stir the crème anglaise with the 1/2 cup of dulce de leche and the butter. Whisk in the egg whites. Add the challah, stirring and gently mashing until the cubes are nearly soaked, 2 to 3 minutes. Transfer the bread mixture to the prepared baking dish and bake for about 12 minutes, until firm and bubbling around the edges.
Heat the broiler. Broil the pudding for 1 to 2 minutes, shifting the dish a few times, until browned all over. Cut the bread pudding into squares, drizzle with dulce de leche and serve.
More Saucy Ideas: Serve the crème anglaise as a sauce for fresh berries or poached fruit; spoon it over pound cake or chocolate cake; or use it as a base for making ice cream.