Step 1 Whisk together the egg yolks in a small bowl. Place the finely chopped chocolate in a large glass or plastic bowl.
Step 2 In a medium, heavy-bottom saucepan, combine the milk, cream, corn syrup and orange zest. Bring the mixture to a boil over high heat. When it has come to a boil, remove from heat and whisk one-half cup of the milk mixture into the eggs. (This will warm, or "temper," the eggs.)
Step 3Stir the tempered egg mixture back into the saucepan with a wooden spoon and heat over medium heat. Cook, stirring constantly, just until the mixture thickens to a custard and will coat the back of the spoon. Immediately remove from heat and strain the custard into the bowl containing the chocolate.
Step 4Quickly stir the custard with the chocolate until the chocolate is completely melted and the mixture is smooth. Divide the custard between each of 4 individual serving bowls or glasses. Refrigerate the bowls, uncovered, until the custard is set (a pudding-like consistency), a couple of hours up to overnight.