In a medium saucepan, combine the water, 2 1/2 tablespoons of sugar, salt, and 2 tablespoons of vegetable oil. Bring the mixture to a rolling boil over medium-high heat.

Once boiling, remove the saucepan from the heat and immediately stir in the flour using a wooden spoon. Mix vigorously until the dough forms a smooth ball and pulls away from the sides of the pan, about 1 minute.

Transfer the warm dough to a sturdy piping bag fitted with a large star tip. Let the dough rest for about 5 minutes so it is cool enough to handle safely without burning your hands.

Heat 2 cups of vegetable oil in a deep skillet or heavy-bottomed pot over medium heat until it reaches 375°F (190°C). Meanwhile, whisk together the 1/2 cup of sugar and ground cinnamon in a shallow dish.

Carefully pipe 4 to 6-inch strips of dough directly into the hot oil, using kitchen scissors or a knife to snip the dough from the piping tip. Fry only 3 to 4 churros at a time to avoid dropping the oil temperature.

Fry the churros for about 2 to 3 minutes per side, or until they are deeply golden brown and crispy. Use tongs to transfer them to a paper towel-lined plate to drain excess oil for about 30 seconds.

While still warm, roll the fried churros in the prepared cinnamon-sugar mixture until evenly coated. Serve immediately alongside a warm chocolate dipping sauce, caramel, or a strong cup of coffee.