Heat oil (1 to 1 1/2 inches deep) to 360 degrees in fry pan. Heat 2 cups water, 1 cup butter and 1/2 tsp salt to rolling boil in large saucepan. Meanwhile, mix 1/2 cup sugar and 1 tsp cinnamon in a small bowl and then pour onto a plate. When water mixture boils, stir in 2 cups flour. Stir vigorously over low heat until mixture forms a ball, about 1 minute. Remove from heat.
Beat in 4 eggs (already slightly beaten) all at once. Continue beating until smooth. (It takes a while). Add up to 4 TB water if necessary. Batter will be thick.
Spoon mixture into decorators' tube with large star tip (or in a bag without a tip). Squeeze long strips (about 6 inches) into hot oil. Fry 3 at a time until golden brown, turning once about 2 minutes on each side. Drain on paper towels. Roll churros in sugar/cinnamon mixture. Buen Provecho!
