For the churros, bring the water to a boil in a saucepan along with the butter. Then stir the hot butter-water mixture into the flour until it forms a uniform and smooth consistency. Allow the mixture to cool slightly until lukewarm.
Heat the oil in a wide saucepan. If you hold a toothpick in the oil and bubbles settle on it, the oil is hot enough. Stir the eggs into the lukewarm batter until smooth.
Pour the finished batter into a sugar gun or piping bag and pipe evenly long churros into the oil. Turn after only a short time.
The churros will take no more than 1-2 minutes if the oil is at the right temperature. Drain the finished churros on a tray with paper towels.
For rolling, mix granulated sugar and cinnamon, roll the still warm churros in it.