Gather all ingredients.
Whisk together beef broth, soy sauce, brown sugar, cornstarch, ginger, garlic, and rice vinegar in a bowl until combined and sugar and cornstarch are dissolved; set aside.
Heat 2 tablespoons of the oil in a large skillet over medium-high heat until shimmering. Add onion, and cook, stirring occasionally, until softened, about 2 minutes. Add broccoli, and cook, stirring occasionally, until bright green, tender-crisp, and onion is browned, 6 to 7 minutes. Transfer to a plate. Do not wipe skillet clean.
Reduce the heat to medium, and add remaining 1 tablespoon oil to skillet. Add ground beef and salt, and cook, stirring often to break meat into even crumbles, until browned and cooked through, about 5 minutes.
Whisk broth mixture again, and pour into skillet. Cook over medium heat, stirring constantly, until sauce thickens slightly, 3 to 5 minutes. Return broccoli mixture to skillet, and cook, stirring occasionally, until sauce evenly coats meat and vegetables, 3 to 4 minutes.
Serve over rice, and garnish with scallions and toasted sesame seeds. Recipe developed by Catherine Jessee
