Thinly slice the flank steak or skirt steak against the grain. Combine in a bowl with soy sauce, peanut oil, and cornstarch, and marinate for at least 10 minutes.

In a separate bowl, whisk together chicken stock, Shaoxing wine, soy sauce, brown sugar, and cornstarch until smooth.

Heat a large pan over medium heat and add a splash of water. Add broccoli florets, cover, and steam for about 1 minute.

Increase heat to medium-high, add peanut oil, then add marinated beef and sear for about 30 seconds on each side.

Add minced garlic and ginger to the beef and sauté for about 30 seconds until fragrant.

Return steamed broccoli to the pan, pour in the sauce, and stir gently for about 1 minute until thickened.

Remove from heat and transfer to a serving dish. Optionally garnish with sesame seeds and chopped scallions.