Follow these simple steps to culinary success:

1. Prepare the Sauce: In a small bowl, whisk together the low-sodium soy sauce, oyster sauce (if using), rice vinegar, honey or brown sugar, sesame oil, ground ginger, and red pepper flakes (if using). Set aside. This allows the flavors to meld while you cook the other components.
2. Brown the Beef: Heat the olive oil in a large skillet or wok over medium-high heat. Add the ground beef and cook, breaking it apart with a spoon, until browned, about 5-7 minutes. Drain off any excess grease.
3. Sauté Aromatics: Add the chopped onion to the skillet with the beef. Cook, stirring frequently, until the onion is softened and translucent, about 3-4 minutes. Add the minced garlic and cook for another minute until fragrant, being careful not to burn it.
4. Cook Green Beans: Add the trimmed and cut green beans and the beef broth (or water) to the skillet. Stir everything together, then cover the skillet and cook for 5-7 minutes, or until the green beans are tender-crisp. The cooking time will depend on the thickness of your beans and your desired level of tenderness. Stir occasionally to ensure even cooking.
5. Combine and Thicken: Pour the prepared sauce mixture over the beef and green beans. Stir well to coat everything evenly. Bring the mixture to a gentle simmer.
6. Add Cornstarch Slurry: Give the cornstarch and cold water mixture a quick whisk to ensure it’s smooth. Pour the slurry into the simmering skillet, stirring constantly. Continue to cook and stir for 1-2 minutes, or until the sauce has thickened to your desired consistency.
7. Serve: Remove the skillet from the heat. Taste and adjust seasonings if necessary (you might want a little more soy sauce or a pinch of sugar). Serve immediately, garnished with sesame seeds and sliced green onions, if desired.