Beef and oyster sauce stir-fry

Name: Beef and oyster sauce stir-fry
Prep time: 20 min
Cook time: 17 min
Total time: 37 min
Cuisine: Asian
Ingredients: 1/4 cup oyster sauce; 2 tbsp dark soy sauce; 1 tbsp shao hsing (Chinese rice wine); 2 tsp cornflour; 500g beef rump steak, trimmed, thinly sliced; 2 tbsp vegetable oil; 4 green onions, cut into 2cm lengths; 2 garlic cloves, finely chopped; 1 bunch baby choy sum, trimmed, stems and leaves chopped; 2 zucchini, halved lengthways, sliced diagonally; Steamed jasmine rice, to serve