Make a marinade in a medium bowl by whisking together soy sauce, sherry, cornstarch, honey, and sesame oil.
Add sliced beef (cut against the grain in ¼” thick slices) and coat. Set aside for at least 15 minutes at room temperature, or refrigerate if marinating longer.
Make the sauce in a medium bowl by whisking together beef stock, oyster sauce, soy sauce, sherry, and cornstarch until the cornstarch is dissolved and no white lumps remain. Set aside.
Heat a wok or large saute pan over high heat. Add ⅓ cup water and bring to a boil.
Add broccoli to the wok and saute until just tender and bright green, about 3 minutes. Transfer broccoli to a bowl and set aside.
Dry the wok with a paper towel then set heat to medium-high until very hot.
Add vegetable oil to the wok. Once the oil is hot, add the ginger and garlic clove, sauté for 30 seconds.
Add the marinated beef in a single layer, cook without moving for 1 minute. Stir fry until no longer pink, about 1 minute.
Add the sauce to the wok and bring to a rapid simmer, stirring occasionally until thickened, about 1 to 2 minutes.
Add the cooked broccoli and red bell peppers to the wok, stir-fry for an additional 1 to 2 minutes to warm.
Season with pepper to taste. Serve immediately with rice if desired.