Step 1
Sift the flour and baking powder into a large bowl. Add the polenta, sugar and salt. Stir until combined. Make a well in the centre. Place the egg and 250ml (1 cup) milk in a bowl and whisk until combined. Pour into the flour mixture then whisk until combined and smooth. Set aside for 15 minutes to rest.
Step 2
Meanwhile, pour oil into a large wide saucepan until half full. Place over medium- high heat and heat to 180°C on a cook’s thermometer (see tip). Insert paddle-pop sticks into the frankfurts, leaving a ‘handle’ about 5cm long. Pat dry frankfurts with paper towel.
Step 3
Stir the remaining milk into the flour mixture. Place extra flour on a plate then lightly dust the frankfurts, shaking off excess. Hold the ‘handle’ of 1 frankfurt and dip into the batter. Use a spoon to spoon over more batter to coat completely. (The batter will start to run off, so twist as you lift out.) Gently drop the frankfurt into the hot oil. Repeat with 2 more frankfurts, gently dropping into the hot oil.