In a small bowl, whisk 1/2 cup of the milk with the cornstarch, vanilla and salt until smooth. In a large saucepan, combine the sugar with 1/4 cup plus 2 tablespoons of water and bring to a boil. Cook over moderately high heat, undisturbed, until a deep amber caramel forms, about 8 minutes. Remove from the heat. Very gradually whisk in the remaining 3 1/2 cups of milk, 1/4 cup at a time. Whisk over moderate heat until the caramel has dissolved. Simmer over moderately low heat until the mixture thickens slightly and deepens in color, about 10 minutes. Remove from the heat.
Gradually whisk the cornstarch mixture into the caramel. Cook over moderate heat, stirring, until the pudding is very thick, about 1 minute. Strain the pudding through a fine strainer set over a large measuring cup. Scrape the pudding into eight 1/2-cup ramekins and refrigerate until chilled, about 2 hours. Garnish with nut brittle, if desired.
The pudding can be refrigerated for up to 2 days.
One Serving 220 cal, 3 gm fat, 1.5 gm sat fat, 50 gm carb, 0 gm fiber.