In a 3-quart saucepan combine water, cinnamon stick, salt and vanilla. Bring to a boil. Discard cinnamon stick and add flour all at once. Stir dough using a wooden spoon until it forms into a ball, about 2 – 3 minutes. Remove from heat, set aside to cool slightly.
Working quickly, add egg and beat vigorously to form a smooth slightly sticky dough. Transfer to a pastry bag with a large star tip. Set aside.
In a dutch oven, add oil and heat to 375 degrees.
Once oil is heated, carefully pipe strands of the dough directly into the oil and using a pair of clean scissors or a sharp knife, cut the dough once the strip is long enough. Cook in oil, turning the churros to cook evenly, for 2-3 minutes each or until golden brown.
Remove churros from oil and place on paper towel to soak up excess oil for 1 minute. While still hot, transfer to cinnamon sugar mixture to coat. Move to serving tray and place in oven on warm or enjoy while fresh.
Bring oil back up to temperature before starting the next batch.