Bring 1 3/4 cups of water to a boil in a large saucepan with 2 sticks of butter and 1/2 teaspoon of salt. Remove the pan from heat and stir in flour until completely incorporated. Return the pan to moderate heat and cook until the dough pulls away from the sides, stirring constantly. Remove from heat and add dough to the bowl of an electric stand mixer.

Beat the dough with an electric mixer on low for one minute to cool the dough. Then increase the speed to medium-high and add the eggs and egg white one at a time. Cover the dough in the mixing bowl with a sheet of plastic wrap, pressing the plastic to the surface, and refrigerate until the dough is room temperature - about 15 minutes.

While the dough is cooling, heat the milk in a medium saucepan until simmering. Add 1 stick of butter and light corn syrup, heat until the butter is melted. Pour the chocolate chips to a separate bowl and slowly pour the warm milk mixture over the chocolate, whisking constantly until the chocolate is completely melted and the mixture is smooth. Add 1/2 Tbsp cinnamon and stir to combine. Add the dipping chocolate back to the saucepan and keep warm over low heat.

Heat the oil to 375° in a flameproof dutch oven or large saucepan. Prepare a baking sheet with a layer of paper towels. In a medium bowl, combine the remaining sugar and cinnamon. Next, add the dough to a large pastry bag fitted with a medium-small star tip.

Squeeze 4 to 5-inch lengths of the dough into the hot oil, cutting them off with a knife. Fry over moderately high heat, turning once or twice, until browned, about 8 minutes. Remember not to overcrowd the pan! Drain the churros on the rack for about one minute and then sprinkle with cinnamon sugar. Serve immediately with the chocolate dipping sauce.