1-First: tenderise the beef by slicing it thinly, about 3-4mm thick and 4-5cm long. Coat it evenly with 1/2 tsp baking soda and let it sit for 20 minutes. Then, rinse under cold water using a colander and pat dry with paper towels.

2-Next: mix all sauce ingredients except cornstarch and water. Reserve 1 1/2 tbsp for coating the beef, then add cornstarch to the remaining sauce to form a smooth mixture, and incorporate the reserved water.

3-Heat 1 1/2 tbsp peanut oil in a wok or large non-stick pan over high heat. Quickly cook the sliced onion and garlic for about 10 seconds until the garlic turns golden.

4-Add the beef and stir continuously until its color changes from red to brown but is not fully cooked. Then, add carrot, capsicum, bok choy stems, and the white parts of green onions; stir for 1 to 1.5 minutes, keeping veggies crisp.

5-Pour in the sauce mixture and stir until it bubbles and thickens. Finally, add bok choy leaves and green parts of green onions, tossing for 30 seconds to 1 minute until leaves wilt and sauce becomes glossy. Serve immediately over steamed white rice and optionally garnish with sesame seeds.