Rinse shredded potatoes until the water runs clear. Drain and squeeze dry. 

Place potatoes in a bowl and mix in the onion, flour, and egg until evenly distributed.

Heat about 1/4 inch of oil in a heavy skillet over medium-high heat. When oil is hot, place potatoes into the pan about 1/2 inch thick. You can either cook all the potatoes in one layer or you can create smaller pancake shaped groups of potatoes (which I find easier). 

Cook until the potatoes are browned on the top, flip and cook until brown on the other side, at least 5 minutes per side. 

Remove from pan and drain on paper towels.

Season with salt and pepper and serve hot.