Bring the milk with the lemon peel and the cinnamon stick to a boil. Lower the heat and simmer 10 minutes.

In a saucepan, beat the egg yolks with a wire whisk until they are lemon colored. Beat in the granulated sugar, then the cornstarch. Stir in a few tablespoons of the hot milk, then gradually stir in the rest. Cook over moderate heat, stirring constantly, until thickened and smooth. Remove at the first sign of a boil. Discard the lemon peel and cinnamon stick. Give the custard a vigorous stir to release steam, then pour into a greased 8-inch square pan. Let cool, undisturbed, then refrigerate until the custard becomes hard.

Cut the custard into 2-inch squares, dip them in the beaten egg, then coat with bread crumbs. Fry in very hot oil, at least ½ inch deep. Drain, dust with a mixture of powdered sugar and cinnamon, and serve immediately. Leche Frita can be kept warm if necessary for about 30 minutes in a 200°F oven.