Heat oil in a large skillet over high. Add beef, and press into a thin layer covering bottom of skillet. Cook, stirring once, until browned, about 6 minutes. Add broccoli and garlic. Cook, stirring occasionally, until broccoli begins to soften, about 6 minutes. Add rice and bell pepper. Cook, stirring often, until heated through and beginning to brown, about 6 minutes.

Stir together soy sauce, vinegar, sesame oil, and brown sugar in a small bowl. Pour soy mixture over rice mixture, stirring to combine.

Remove from heat; sprinkle with scallions, salt, and crushed red pepper.