Place water, butter, sugar, and salt into a medium saucepan. Bring to a boil.

Add flour and mix vigorously until dough balls up, and everything is well blended. Remove from heat.

Place dough into the bowl of a stand mixer fitted with a paddle attachment. Mix on low until steam disappears. 

Add eggs one at a time while the machine is on. Turn speed up to medium, and mix until fully incorporated before repeating with second egg. 

Scoop dough into a piping bag fitted with a star piping tip. (I used a Wilton 2D tip. Make sure the tip is slightly rounded -- helps prevent churros from splitting.) Combine cinnamon and sugar on a large plate and set aside.

Heat oil in a large frying pan or stock pot to 350-375 degrees Fahrenheit. To test the oil for frying, drop a tiny piece of dough into the oil. Once it browns, you are ready to pipe the churros in. 

Pipe the dough directly into the hot oil to desired length (about 5-inches) and cut with a fork, knife, or scissors. Straighten churros with the cutting utensil if needed. Do not pipe too many churros at once. (So they cook evenly.)

Cook churros about 2 minutes (1 minute on each side) or until golden brown.

Remove churros and place on a paper towel to absorb excess oil. While still warm, roll churros in cinnamon-sugar mixture. Serve with dulce de leche or chocolate sauce, if desired.