Rinse Chinese broccoli under cold water, then trim tough ends. Pat dry and cut into 3-inch lengths, reserving tender leaves.

Warm 2 tablespoons vegetable oil in a large wok over medium-high heat until it shimmers, about 1 minute.

Add minced garlic to the hot oil, stirring constantly. Cook for about 30 seconds until edges turn light golden.

Toss in broccoli stems first, stirring for 1 minute until they turn bright green and begin to soften. Then add the reserved leaves, stirring until they just wilt.

Stir together soy sauce, oyster sauce (optional), a pinch of sugar, and 2 tablespoons water or broth. Pour over the broccoli, tossing quickly to coat every piece.

Cover the wok, reduce heat to medium, and steam for 2–3 minutes until crisp-tender.

Transfer to a warm plate, drizzle any accumulated sauce from the wok over the top, and serve immediately.