Thinly slice the beef, onion, red bird's eye chili, green chili, and spring onion.

Pound the 4 cloves of garlic and 1.3 cm ginger into a coarse paste.

Place the 500 g sliced beef in a dry wok over medium-high heat.

Cook the beef in its released juices until the liquid has mostly evaporated, about 8 minutes.

Add 1 tbsp cooking oil and the pounded garlic-ginger paste to the wok.

Add 1/2 tsp ground turmeric and 1 tsp seasoning powder.

Stir-fry until the beef is evenly yellow and fragrant, about 2 minutes.

Pour in 2 tbsp oyster sauce and 2 tbsp chili sauce.

Add 1 tbsp tomato sauce and 1 tbsp sweet soy sauce.

Stir the sauces through the beef until every slice is coated.

Add 2 tbsp water and bring the sauce to a gentle boil.

Simmer until the sauce becomes glossy, thick, and clings to the beef, about 5 minutes.

Add the sliced red bird's eye chili, green chili, and onion.

Stir-fry until the onion softens slightly while remaining crisp, about 2 minutes.

Add the sliced spring onion and stir briefly.

Remove from the heat and serve the saucy beef hot, preferably with steamed white rice.