2 cups water
3 tablespoons unsalted butter
3 tablespoons granulated sugar, plus 1/2 cup for rolling
2 1/2 cups all-purpose flour
Pinch of salt
2 eggs, at room temperature
Canola oil for deep frying
3 tablespoons unsweetened cocoa powder
In a medium saucepan over medium heat, combine the water, butter, and 3 tablespoons sugar. Bring to a boil, and cook, stirring constantly, until the butter is completely melted and the sugar is dissolved. Remove from the heat. Add the flour quickly, all at once. Using a sturdy whisk, stir until smooth. Add the salt. Let rest for 2 minutes. Then add the eggs, one at at me.
Heat 3 inches of oil in a deep, heavy pot to 375°F, or in a deep-fryer according to the manufacturer's instructions, until a piece of dried bread floats and turns golden in the oil after 1 minute.
Spread the remaining granulated sugar and unsweetened cocoa on a plate.
Spoon the batter into a churro maker or pastry bag. Squeeze five or six 3-inch lengths of the mixture into the hot oil, using a knife to slice off each length as it emerges from the nozzle. Cook the churros, in batches as needed, until golden. Quickly drain on paper towels and roll in the sugar mixture while still warm. Serve immediately.
Churros, Spanish doughnuts beloved throughout the New World, easily marry with so many flavors, from chocolate to fruit sauces. Although they are traditionally shaped with a churrera, a tool with a plastic or wooden plunger that extrudes the dough into its traditional fluted shape (which is key, or they turn out hard and doughy), I recommend spooning the mixture into a cake decorators' pastry bag with a 2-inch star tip (the kind used to decorate cakes).