In a sauce pan combine the water, salt, butter and lemon zest (vanilla if using) and cook on medium heat.
Once it starts boiling, add the flour. Using a wooden spoon, keep stirring! Don’t get distracted because you will have a big ball of dough very soon.
Once you have a big ball of dough, place it into your your piping bag (if you don’t have one, just use a Ziploc bag and cut the corner of the bag).
In a deep pot heat the oil for frying to 375F (you can also use a fryer). Pipe 5 inch long straight line of dough (or any size you desire…) into the hot oil using the pastry bag fitted with a medium star tip.
Note* You can also pipe the dough on a sheet and then fry the churros.
Cook until they get a nice golden brown color (Do not overcrowd the oil) . Remove from the pan and place on a plate lined with paper towels to remove the excess oil.
Roll drained churros in sugar.