1. 1. In a saucepan, heat the whole milk with the granulated sugar, cinnamon stick, lemon peel, and orange peel over medium heat until hot but not boiling. Remove the cinnamon stick and citrus peels.

2. 2. In a separate bowl, whisk the cornstarch and all-purpose flour with a bit of warm milk until smooth. Slowly pour this mixture into the saucepan, stirring constantly until thick and creamy.

3. 3. Pour the thickened mixture into a lightly greased baking dish, smooth the top, and cool completely. Refrigerate for at least 2 hours until firm.

4. 4. Cut the chilled custard into squares or rectangles. Beat the eggs in one bowl and place the flour in another. Dip each piece of custard first in the flour, then in the beaten egg.

5. 5. Heat sunflower oil in a pan over medium-high heat. Fry the coated custard pieces until golden brown on all sides. Drain on paper towels.

6. 6. Mix the white sugar and ground cinnamon in a small bowl. Sprinkle over warm Leche Frita pieces and serve warm or at room temperature.