Combine cornstarch and 2 Tablespoons cold water in a covered container and shake to combine. Place in a cool location. Combine remaining sauce ingredients in a medium bowl and set aside.

Heat peanut oil over medium heat. Add broccoli and toss to coat. Cook for 4-5 minutes, until slightly softened. Remove and set aside.

Season ground beef with salt/white pepper if desired. Cook and crumble the ground beef and diced onion over medium-high heat until browned and cooked through. Drain grease. Add sliced bell pepper and cook for 1 minute.

Add sauce mixture and bring to a boil. Let it simmer/reduce for 2-3 minutes. Shake cornstarch mixture, then slowly stir it into the sauce. Let it continue to bubble gently until desired thickness is obtained.

Reduce heat to low. Add broccoli back and stir to combine and heat through. Serve over rice.