Step 1

Slice the cooked steak into thin strips, trimming off any fat around it if desired.

Step 2

Combine oyster sauce, soy sauce, fish sauce and water in a small bowl and stir to combine.

Step 3

Add just enough oil in a wok to coat the bottom, then add the garlic and saute over medium heat until the smallest bits start to turn golden.

Step 4

Add the black pepper and stir to mix with the oil. Add onions and bell pepper, and toss for about 1 minute or longer if you prefer the softer vegetables.

Step 5

Once the vegetables are cooked almost to your liking, add the sauce and toss for about 10 seconds. Turn the heat up to high then add the sliced steak; if you like the doneness of the steak as is, just toss it briefly (20-30 seconds) until heated though, otherwise cook it longer to get the desired doneness. Since the steak is already cooked, you only need to cook it long enough to heat it through.