Sift flour, sugar, baking soda, baking powder and salt together; set aside. Mix egg and milk together; add to flour mixture. Stir until batter is smooth. Pour oil into a deep skillet to a depth of one inch; heat oil over medium heat to 375 degrees on a candy thermometer. Holding a finger over the spout of a funnel, pour 1/4 cup batter into the funnel. Release your finger and allow batter to flow into the hot oil, spiraling batter to form cake. Fry for 2 minutes on each side or until golden brown; drain and sprinkle with powdered sugar.