In a medium bowl, mix together soy sauce, oyster sauce, and cornstarch solution. Set aside.
Heat 1 tablespoon of oil on the Blackstone griddle over medium-high heat. Add the beef strips, season with salt and pepper, and stir-fry until browned. Remove and set aside.
Add remaining oil to the griddle. Cook the garlic and ginger until fragrant, about 30 seconds.
Add the bell peppers and onion. Stir-fry for about 2-3 minutes until they start to soften.
Return the beef to the griddle, add the sauce mixture, and stir well to combine. Pour in the beef broth and simmer until the sauce thickens.
Serve hot with rice or noodles.
Notes
Ensure the beef is sliced thinly for a quick cooking process. Adjust seasoning according to taste.