Prepare the cinnamon sugar coating: In a large bowl, whisk together 1/2 cup sugar, cinnamon, and a pinch of salt. Set aside.
Heat the oil: In a deep fryer or large heavy pot, heat oil to 375°F (190°C). Use a candy thermometer to monitor temperature.
Make the choux pastry: In a large saucepan, combine water, butter, 1 tablespoon sugar, and 1/2 teaspoon salt. Bring to a rolling boil over medium-high heat.
Add flour: Remove from heat and immediately add all the flour at once. Stir vigorously with a wooden spoon until mixture forms a ball and pulls away from sides of pan.
Cook the paste: Return pan to medium heat and cook, stirring constantly, for 1-2 minutes to cook out raw flour taste.
Cool slightly: Transfer mixture to a bowl and let cool for 5 minutes.
Add eggs: Beat in eggs one at a time, mixing well after each addition until smooth. Stir in vanilla extract. The batter should be thick but pipeable.
Fry the churro bites: Using a small cookie scoop or spoon, carefully drop 1-tablespoon portions of batter into the hot oil. Don't overcrowd - fry 6-8 pieces at a time.
Cook until golden: Fry for 3-4 minutes, turning occasionally, until golden brown and puffed. They should sound hollow when tapped.
Drain: Remove with slotted spoon and drain on paper towel-lined plate for 30 seconds.
Coat in cinnamon sugar: While still warm, toss churro bites in cinnamon sugar mixture until completely coated.
Serve: Serve immediately while warm and crispy.