Combine 1½ cups sugar and the cinnamon in a large mixing bowl and set aside. Break the eggs into a liquid measuring cup or spouted pitcher and set aside.
Place the water, butter, ¼ cup sugar, and salt in a heavy saucepan over medium-high heat. Bring to a simmer. Add the flour all at once and stir with a wooden spoon until it forms a thick dough. Continue to cook while stirring for about 1 minute.
Put the dough into a pastry bag with a large round or star tip and pipe out 6-inch lengths of dough directly into the hot oil. Fry for 2-3 minutes per side or until golden brown. Remove with a slotted spoon, let the excess oil drip off, then place the churros into the cinnamon sugar mixture. Toss gently to coat. Continue until all the dough is cooked. Serve with the chocolate dipping sauce.