In a small stockpot, heat 1-inch of vegetable oil to 375℉.
In a large bowl, whisk together flour, sugar, baking powder, and salt.
Add eggs, milk, and vanilla.
Whisk until smooth.
Ladle batter into a pastry bag or plastic zip top bag.
Snip the tip off the bag so that you have about a ¼" opening.
Beginning in the middle of the stockpot, pipe batter into hot oil in a swirling pattern.
Cook until light golden brown, about 1 minute.
Flip over.
Cook for 1 minute.
Remove from oil using a spider or slotted spoon.
Drain.
Repeat with remaining batter.
Sift powdered sugar over top and serve.