Preheat the oven to 400°F (200°C). Line a large baking sheet with parchment paper. Lightly oil the paper with cooking oil spray. Set aside.

Prepare a sturdy piping bag- not a plastic one, it will crack. You need a pastry chef silicone bag that holds pressure and temperature. Mount the bag with a large star tip - it has to be large or the batter will not extract nicely. I like to place my piping bag in a tall glass so it's easier to fill quickly with the churros batter.

In a large baking dish, prepare the cinnamon-sugar mixture by stirring the cinnamon and sugar evenly. Set aside.

In a mixing bowl, whisk flour and sugar. Set aside.

In a non-stick saucepan, add water and oil, and place a lid on. Bring to a medium-high heat until it reaches a high boil.

When the water boils, remove the lid and remove from the heat.

Immediately pour the flour into the saucepan, and stir energetically with a wooden spoon or rubber spatula to form a soft, elastic dough ball.

Pour the batter into the piping bag and pipe logs of dough on the prepared baking sheet. The length of the churros doesn't matter, I like 4-inch/10 cm churros. You can make them shorter or longer. Pipe the dough fast because it gets difficult to pipe the batter as it gets colder. Cut the ends of the churros with scissors when the desired length is achieved.

If you struggle with piping the dough, simply roll 5-inch-long logs of dough and use the back of a fork to mark the logs.

Place each of the churros on the baking sheet, leaving a little space between each, they won't expand in the oven.

When you have piped all the dough, use a pastry brush to brush each lightly with oil.

Bake the churros for 25 minutes on the top rack at 400°F (200°C). Watch them closely and remove any churro that turns golden brown before the other. Keep baking the remaining churros in 3-minute bursts until they have a light golden color.

Remove the warm churros from the oven and place them on the baking dish with cinnamon sugar. Use your hands or tongs to toss and coat the churros evenly with the sugar.