Spanish Churros con Chocolate

Name: Spanish Churros con Chocolate
Cuisine: European, Mediterranean, Spanish
Ingredients: 1 cup water; 2 tbsp unsalted butter; 1 tbsp granulated sugar; 1/4 tsp salt; 1 cup all-purpose flour; 2 large eggs; Vegetable oil, for frying; 1 cup whole milk; 100g dark chocolate (70% cocoa), chopped; 1 tbsp corn starch; 1-2 tbsp sugar (adjust to taste); Granulated sugar, for coating; Ground cinnamon, for dusting