In a large Dutch oven, pour oil to halfway full, and heat over medium heat until a deep fry thermometer registers 350°F.

In a medium saucepan, bring 1 cup water, butter, 1 tablespoon (12 grams) sugar, and salt to a boil over medium heat. Reduce heat to low. Add flour, and stir well. Cook over low heat for 2 minutes. Remove from heat, and let cool for 15 minutes.

Transfer mixture to the bowl of a stand mixer fitted with the paddle attachment. With mixer on medium speed, add eggs, one at a time, beating well after each addition.

Place dough in a pastry bag fitted with a large star tip. Quickly dip a flat spatula into oil. Pipe spiral round onto spatula. Gently slide round off spatula into oil. Fry dough for 5 minutes per side.

In a medium bowl, stir together cinnamon and remaining ½ cup (100 grams) sugar. Toss churros in cinnamon sugar. Serve immediately.