1.Heat milk in a heavy saucepan over a medium-high flame until it begins to simmer, then remove from heat.
2.Whisk together the egg yolks, sugar and corn syrup in a metal bowl until blended. Form a kitchen towel into a ring and place the bowl on top to prevent it from moving.
3.Gradually add the hot milk into the egg mixture, whisking constantly. Once fully combined pour the mixture back into the saucepan and and place over a medium-low heat. Cook, stirring slowly with a wooden spatula until the custard thickens and leaves a path on the back of the spatula when a finger is run across it. It will take about 6 minutes. Be sure not to let it boil.
4.Pour the custard through a medium mesh strainer/sieve set over a clean metal bowl. Add the chocolate and cocoa and stir until the chocolate melts. Refrigerate the custard until cold, about 1 hour.
5.Transfer the custard to an ice cream maker and process according to the manufacturer’s instructions. For the best texture serve the gelato immediately. Or transfer to an ice cream container (I just bought one of these, they are great for any ice cream, frozen yogurt, or gelato) and freeze until firm. The gelato texture could last up to 3 days, but after that it starts to that the consistency of ice cream. Enjoy every spoonful!