Preheat oven to 450 degrees F. Spray a large, rimmed baking sheet with cooking spray (if desired, line with foil first for easy cleanup). Set aside.
In a small bowl, whisk together soy sauce, garlic, brown sugar, ginger, and pepper. Set aside.
Place beef, bell peppers, and onion in a single layer on the prepared baking sheet.
Pour half of the sauce (about 1/3 cup) over top and toss to coat.
Roast beef and vegetables for 10-14 minutes, or until beef is cooked to desired doneness (about 145 degrees F for medium-rare). Toss with reserved sauce.
Garnish with sesame seeds and sliced green onions. Serve over rice, if desired.
Source:
theseasonedmom.com