Slice beef against the grain into 2-3mm slices and put them into a mixing bowl I butterflied each slice to make each slice of beef larger
Add 1 tbsp water, 1 tsp light soy sauce, ½ tsp dark soy sauce, ½ tsp sugar, ⅛ tsp white pepper powder, ⅛ tsp garlic powder and mix well with your hand. Squeeze the beef slightly so that it absorbs all the water
Add 1 more tbsp water to the beef and continue mixing and squeezing until all the water is absorbed
Add 2 tsp potato starch. Mix and squeeze until mixed well and starch is no longer white
Add 1 tsp sesame oil and mix well. Set aside to marinate for 30 minutes
Slice celery to your desired length and shape
Mince shallots, chop garlic and cut chili Add more chilis if you like it spicier
Cut green onions to your desired length. Separate the white parts of the onions from the green parts
In a hot wok, using high heat, add 2 tbsp oil. Use a spatula to move the oil around the wok to prevent sticking
Loosen and mix the beef one last time and add to the wok If you have any water unabsorbed by the beef, pour it out before putting everything into the wok. It can cause a lot of oil splatter and your beef will not come out tender
Arrange beef in single layer and let cook for 40 seconds (if beef is thicker than 3mm, then cook for 1 minute)
Flip beef over and fry for another 30 seconds. Remove beef from wok and turn down heat to medium
Use the leftover oil to fry the shallots, garlic, and the whites of the green onions. If there was no oil remaining from frying the beef, then add 1 tbsp oil
Make a well in the centre of the wok and add 2 tbsp Sha Cha Sauce and ½ tsp sugar. Fry for 1 minute and turn heat to medium-high
Add celery and stir-fry until your desired doneness (crispiness of the celery). I stir-fry the celery for approx. 2 minutes so that the celery is slightly wilted but still has some crispiness
Turn heat to high, add beef and the rest of the green onions. Add 1 tbsp Shaoxing wine around the wok edge so that the wine can slide down to the bottom of the wok
Stir-fry everything together for 1 minute
Add chilis and mix well
Serve