Khalva - Syrupy Walnut Dessert

In a enameled saucepan, combine 1 1/2 c milk with sugar and, stirring constantly, cook over moderate heat until the sugar is dissolves. Stir the cornstarch into the remaining milk, then pour into the milk-sugar mixture. Bring to a boil and cook until the mixture thickens to a custard-like consistency. Set aside off the heat. Preheat the oven to 200 C. Combine the walnuts with the melted butter in a mixing bowl, and toss them with a wooden spoon until they are completely coated. Then spread them out in a shallow, heavy pan. Toast them in the oven for about 20 minutes turning them frequently with a large spoon until they are deep brown. Pour the custard evenly over the nuts, cover the pan with foil, and bake for 15 or 20 minutes, until the custard is thick and syrupy. Serve at once.