Fill main bowl up to steam line with hot water. Peel and chop potatoes into approx 3 cm squares and place in large steaming basket. Steam at 140°C for 20 to 30 minutes or until soft. (ours take about 25 minutes.)
Once soft, pour water out of main bowl and using butterfly whip add potatoes, butter and milk and whip speed 6 for approx 30 seconds to 1 minute or until desired consistency. Set aside.
Using multi blade. Add flour, onion, egg, salt and pepper. Pulse for 5 seconds. Scrape down and add in mashed potato. Mix on speed 5 until combined.
Heat a fry pan over medium heat with a light coat of oil. Spoon rounds of potato mix into hot oil and cook on each side for a few minutes each.