Begin by slicing the beef flank or skirt steak against the grain into thin strips. In a medium bowl, combine the beef with Shaoxing wine, a pinch of salt, black pepper, and cornstarch. Mix well to ensure every piece is coated. Let this marinate for about 15 minutes at room temperature.

While the beef marinates, whisk together chicken broth, soy sauce, rice vinegar, sesame oil, and sugar in a small bowl. Add minced garlic for extra flavor. Set the mixture aside.

Heat peanut oil in a large skillet or wok over medium-high heat until shimmering. Add the marinated beef in a single layer and stir-fry for about 2-3 minutes until browned and just cooked through. Remove the beef from the skillet and set aside.

In the same skillet, add the prepared sauce to the hot pan, scraping up any flavorful bits left from the beef. Bring to a gentle boil and simmer for about 2-3 minutes, stirring occasionally until the sauce thickens slightly.

Return the cooked beef to the skillet, toss to coat in the sauce and stir-fry for an additional minute to heat through.

Transfer the sesame beef stir-fry to a serving platter, sprinkle with toasted sesame seeds and serve hot over steamed rice or alongside vegetables.