In a small bowl, whisk together the soy sauce, water, brown sugar, minced garlic, grated ginger, cornstarch, and red pepper flakes until the cornstarch is fully dissolved and the mixture is smooth. Set aside—this ensures the cornstarch won't clump when it hits the hot beef. I like to prepare this first so it's ready to go the moment the meat finishes cooking, which helps build that glossy sauce quickly.

Heat the avocado oil in a large skillet over medium-high heat until it shimmers. Add the sliced white parts of the green onions and the ground beef, breaking it apart with a spoon as it cooks. Cook for 5-7 minutes, stirring occasionally, until the beef is deeply browned and crispy in spots—this develops rich flavor through caramelization. Once cooked through with no pink remaining, carefully pour off excess grease, leaving just enough to coat the pan lightly.

Pour the sauce mixture from Step 1 over the cooked beef, stirring constantly. Cook for 1-2 minutes, allowing the cornstarch to thicken the sauce into a glossy glaze that coats each piece of meat. The sauce will go from thin to thick as the heat activates the cornstarch. I find that keeping the heat at medium-high and stirring continuously prevents the sauce from scorching on the bottom while ensuring even coating. Once the sauce reaches a consistent glaze-like consistency, drizzle in the sesame oil and toss to combine.

Transfer the glazed beef to serving bowls over rice or noodles, then top generously with the sliced green parts of the green onions for a fresh, bright contrast to the rich savory sauce.