How to Make It
Pour oil in a 10-inch cast-iron skillet or other heavy-bottomed pot to a depth of 1 inch and with a deep-fry thermometer; heat to 350°F over medium-high.
Whisk together flour, granulated sugar, baking powder, and salt in a medium bowl. In a separate medium bowl, whisk together milk, vanilla, egg, and 2 tablespoons canola oil. Make a well in the center of the dry ingredients and add milk mixture, whisking until smooth. Transfer batter to a squeeze bottle with a ¼-inch opening. (Or a large ziplock bag, and snip one corner to make a ¼-inch hole.)
Hold bottle or bag one inch from hot oil in the center of the skillet. Carefully squeeze about ¼-cup batter into oil, squeezing in a tight circular motion to begin, and crossing back and forth over circles to create one 6-inch cake. (Do your best to do this is one continuous motion.) Fry, turning once, until golden brown, about 2 minutes per side. Drain on a paper towel-lined baking sheet. Return oil to 350°F between cakes.
Sift powdered sugar over cakes just before serving.