How to Make It
Whisk together flour, sugar, baking powder, and salt in a medium bowl. Add butter; cut into flour using 2 knives or a pastry cutter, until butter is well combined and looks like coarse cornmeal. Add milk, and stir until dough forms a ball. Place dough on a floured surface, and knead until dough is smooth and forms a cohesive ball, about 30 seconds. Cut dough into 14 equal balls. Roll each gently to form evenly smooth balls.
Thoroughly coat bottom of air fryer basket with cooking spray. Place 7 dough balls in the basket of air fryer, spacing evenly to avoid touching. Spray dough balls with cooking spray. Cook at 350°F until browned and puffed, about 10 minutes. Gently remove from basket, and place on a wire rack.
Whisk together powdered sugar and water in a medium bowl until smooth. Place cooked dough balls, 1 at a time, in glaze; roll to coat. Place on wire rack or baking sheet lined with parchment paper to dry.
Repeat procedure with remaining dough and glaze.