Coarsely grate the potatoes into a colander. Rinse with cold water for several seconds.
Use your hands to squeeze out as much excess liquid as possible. Transfer potatoes to a bowl.
Add the flour, egg and salt to the potato, and stir until well combined. Divide mixture into 16-20 equal portions.
Add enough oil to a large deep frying pan to reach a depth of 2cm. Heat to 190°C over medium-high heat (when oil is ready a cube of bread will turn golden brown in 15 seconds).
Spoon 4 portions of potato mixture around the edge of the pan and flatten slightly to form discs. Shallow-fry for 3 minutes or until golden underneath. Turn and shallow-fry for a further 2 minutes or until crisp. Use an egg lifter to transfer hash browns to prepared tray and place in preheated oven to keep warm.
Repeat in 2 more batches with the remaining potato mixture, reheating and topping up oil between batches if necessary.