In a small bowl, combine the chicken broth or water, oyster sauce, rice wine or sherry, sugar and black pepper.

In a separate small bowl, stir the cornstarch into the water. Keep both bowls near the stove

Stir-fry the vegetables. Once the vegetables are stir-fried, push the vegetables to the sides of the wok.

Give the sauce a quick re-stir and pour into the middle of the pan. Bring to a boil.

Give the cornstarch/water mixture and pour into the sauce, stirring quickly to thicken.

Stir to combine the vegetables with the sauce.

Remove the wok from the heat and stir in the sesame oil. Serve, sprinkling the sesame seeds over if desired.