In a medium sauce pan, over medium heat, combine the water, butter, salt, and 1/4 tsp cinnamon. Stir to combine and bring to a full boil.
Reduce heat to low and add the flour, constantly stirring until a ball forms. Allow the dough to rest for about 10 minutes.
Using a electric hand mixer, mix in the egg until well combined.
Heat oil in a skillet or saucepan until the oil reaches 350°.
Spoon the dough into a piping bag fitted with a large star attachment. Alternatively, you can use a zip top bag with the corner cut out.
Pipe and cut the churros to your desired length and fry until a deep golden brown.
Remove with a slotted spoon and let them rest on a paper towel covered plate.
Combine the sugar and remaining 3/4 tsp cinnamon in a large zip top bag and place the churros into the bag, zip the top and shake.