Place the steak strips in a bowl and add the egg. Mix together to thoroughly coat the steak in the egg.

Add the cornflour, salt, pepper, and white pepper. Toss together to coat the steak.

Heat 3 tbsp of the oil in a large frying pan or wok over high heat until very hot.

Add in half the beef – a strip at a time – and spread it out. Fry the steak until dark brown and crispy, about 5 or 6 minutes, stirring about 3 or 4 times.

Using a slotted spoon or tongs, remove the beef from the pan and place in a bowl lined with kitchen roll to soak up excess fat.

Add a further tablespoon of oil and repeat for the second batch of beef.

Once all the beef is removed from the pan, add the remaining ½ tbsp of oil to the pan and turn the heat down to medium.

Add in the sliced onion and cook for 2 minutes until slightly softened.

Add in the finely chopped chilli, minced ginger, and minced garlic. Cook whilst stirring for 30 seconds.

Add the rice vinegar, soy sauce, tomato puree, sugar, tomato ketchup, and sweet chilli sauce to the pan.

Turn up the heat and let it bubble for a couple of minutes until the sauce starts to reduce a little.

Add the beef back in, give it a stir and heat through for 1-2 minutes until the beef is hot. Serve with rice or noodles.