Cut beef into very thin slices, then into 3cm long and 2 cm wide pieces.
Mix well cornstarch with 3 tbsp. water. Mix well in another bowl 1 tbsp. rice wine 1 pinch of salt
and 1/3 of the mixed cornstarch. Add meat and 3 tbsp. of water and mix well. Place 10 minutes covered in the fridge.
Remove seeds and stalks from the peppers and cut them into 2 inch pieces. Peel onions and cut into 2cm pieces also. Wash spring onions, peel garlic and ginger and chop everything fine.
Mix soy sauce with oyster sauce, 1 tbsp. rice wine, sugar, sesame oil, salt and pepper. Stir in the rest of the cornstarch.
Heat 4 tbsp. oil in a wok and fry the beef over high heat, stirring 2-1 minutes and then take out. Sauté spring onions, ginger and garlic over medium heat in the remaining oil, add pieces of pepper and onion and fry everything with stirring for 3 minutes. Add meat. Stir again the mixed oyster soy sauce and pour into the wok. Boil up over high heat, stirring and serve immediately.