Finely chop the onion and reserve 1 tablespoon for garnish. Toss the rest of the shallots with egg milk, bean sprouts, and 20ml of soy sauce until well combined.

Heat 15ml of peanut oil in a large non-stick frying pan over medium-high heat. Scoop the 4 soup key mixed egg mixture into the hot oil and fry for 1-2 minutes. After the bottom is solidified, turn over and fry for another 1-2 minutes, and one cake is cooked. Remove from pan and place on a warm plate while the rest of the pie is cooked.