Pour about 1½" of oil into a heavy deep skillet or deep-fryer and heat oil to 360 degrees F (180 degrees C).
In a medium saucepan, heat water, vanilla, and butter to a rolling boil. Combine the flour and salt; stir into the boiling mixture with a wooden spoon. Reduce heat to low and stir vigorously until the mixture forms a ball, about 1 minute.
Remove from heat and beat in the eggs one at a time. Don't overbeat, mix just until dough reforms into a cohesive ball.
Spoon the mixture into a pastry bag fitted with a large star tip. (Alternatively, scoop dough into a zip-top freezer bag and snip off a corner to pipe out dough).
Carefully squeeze out 3 inch long strips of dough directly into the hot oil. I found scissors worked well to break off the dough where I wanted with minimal splashing of the hot oil.
Fry 4-6 strips at once, until deep golden brown, about 2 minutes on each side. Remove from hot oil to paper towel-lined plate to drain. Stir together the sugar and cinnamon; roll churros in the mixture while still hot, as the next batch is cooking.
Place finished churros on a cooling rack or enjoy as soon as possible without burning your mouth :) These are best enjoyed fresh and warm, as they become softer with storage. If you need to store them, do so in a paper bag, as a plastic bag or container will make the coating very soft.
Recipe by Hidden Ponies at https://hiddenponies.com/2012/06/first-on-the-first-homemade-churros/