Chop the onion roughly and microwave it in a heatproof container covered with plastic wrap for 1 minute at 600W. Drain well and let cool.

Finely chop the beef until it becomes minced.

In a bowl, mix the minced beef, onion, oyster sauce, grated garlic, and salt and pepper. Let it marinate for 10 minutes. In another bowl, mix the flour and water to create the batter.

Add cornstarch to the beef mixture and mix well. Divide into 8 portions and shape into balls. Coat each ball in batter and then breadcrumbs.