Place water, butter, sugars and salt in a saucepan and cook on medium heat until sugar is dissolved. Bring water to a boil and remove from heat.
Add flour to the pot and stir with a wooden spoon or spatula until dough forms.
Add in eggs, one at a time until completely incorporated.
Fill piping bag fitted with a star tip with choux pastry dough.
Heat oil in a large, deep pan until oil reaches 365°F (if not using a candy thermometer you can test the temperature by placing the handle of a wooden spoon into the hot oil, if bubbles start to form around it immediately the oil is hot enough).
While the oil is heating up, prepare cinnamon sugar topping. Mix the sugar and cinnamon in a small bowl and set aside.
Begin piping the churros batter into the hot oil. See instructions for different shapes below.
For the spiral shape: Pipe a spiral of churros batter onto a small square of parchement paper and gently lower it into the hot oil, then remove the paper with tongs.
For regular churros: Pipe directly into the oil and cut the dough using a kitchen scissor, at the desired length.
Fry churros for about 2 minutes on each side. Remove from heat when they are golden brown all around and place directly into the prepared bowl of cinnamon sugar.
Coat in cinnamon sugar and enjoy!