Prepare Cinnamon Sugar Coating: In a shallow bowl or plate, combine 1/4 cup of caster (superfine) sugar with 2 teaspoons of ground cinnamon. Mix thoroughly until the cinnamon is evenly distributed throughout the sugar. Set this bowl aside; it will be used to coat the churros immediately after frying, providing that classic sweet, spicy finish.
Mix Dry Ingredients for Dough: In a heatproof mixing bowl, add 1 cup of plain (all-purpose) flour, 1 teaspoon of baking powder, and a pinch of salt. Use a whisk or fork to combine these dry ingredients evenly. This ensures that the leavening agent and salt are distributed uniformly throughout the flour, which helps the churros cook and rise evenly.
Incorporate Oil and Boiling Water: Carefully add 1 tablespoon of vegetable, canola, or olive oil (avoid extra virgin olive oil due to its low smoke point) to the dry ingredients. Then, slowly pour in 1 cup of boiling water, straight from the kettle. Immediately stir with a wooden spoon or heat-resistant spatula to combine. The mixture will quickly come together into a thick, gummy dough resembling a wet sticky paste. Avoid overmixing — just combine until uniform.
Transfer Dough to Piping Bag: Once the dough is ready, spoon it into a piping bag fitted with an 8mm (about 1/3 inch) star tip nozzle. If you don’t have a piping bag, you can use a sturdy resealable plastic bag with a corner snipped off. Push the dough down to the tip, making sure there are no air pockets. Set the piping bag aside while you prepare the frying oil.
Heat Frying Oil to Correct Temperature: Pour at least 5 cm (2 inches) of vegetable or canola oil into a deep pot, wok, or deep skillet. Heat the oil over medium-high heat until it reaches 170°C (340°F). Use a deep-frying thermometer to monitor the temperature precisely. If you don’t have a thermometer, test by dropping a small cube of bread into the oil — it should turn golden within about 20 seconds. Maintaining this temperature is crucial for golden, crispy churros without being greasy or undercooked.
Pipe Dough into Hot Oil: Hold the piping bag close to the oil surface and pipe 15 cm (6 inch) lengths of dough directly into the hot oil. Use kitchen scissors to snip the dough near the oil surface, preventing splashes. Do 3 to 4 churros per batch, depending on pot size, to avoid overcrowding, which can lower oil temperature and cause soggy results.
Fry Until Golden and Crisp: Allow the churros to cook for 2 to 3 minutes. Use tongs or a slotted spoon to gently turn them occasionally to ensure even frying on all sides. They should puff slightly and develop a golden brown, crisp exterior while remaining soft inside. Adjust heat as needed to keep the oil temperature steady.
Drain Excess Oil and Coat: Using a slotted spoon or spider strainer, carefully lift the fried churros out of the oil and place them on a paper towel-lined plate to drain excess oil. While still warm, roll each churro thoroughly in the prepared cinnamon sugar mixture, coating every surface. This step adds the perfect sweet-spiced crunch.
Prepare the Chocolate Sauce: In a microwave-safe bowl, combine 1/2 cup of dark or semi-sweet chocolate chips with 1/2 cup of heavy cream. Heat in 30-second bursts, stirring well after each, until the chocolate melts completely and the mixture is smooth and glossy. Let it rest for about 5 minutes to cool slightly and thicken to a dipping sauce consistency.
Serve and Enjoy: Arrange the freshly coated churros on a serving plate and serve immediately with the warm chocolate dipping sauce on the side. Churros are best enjoyed hot and fresh for maximum crispness, but they can be reheated in a 180°C (350°F) oven for 5 minutes if needed.