1. Wash bok choy and cut off leaves and reserve.
2. Remove bottom root then cut stems into 1/4 slices and cut leaves into 1/2 strips.
3. Mix cornstarch and soy sauce.
4. Heat oil and butter in skillet over medium high heat until butter is melted.
5. Add gingerroot and garlic then stir fry until garlic is light brown.
6. Stir in pepper then add bok choy stems and stir fry 2 minutes then add water.
7. Cover and cook until stems are crisp tender about 2 minutes.
8. Stir in cornstarch mixture and bok choy leaves.
9. Cook and stir until leaves are wilted about 2 minutes.