1. Sprinkle the black pepper liberally over the steak; rub in slightly. Cut the steak into cubes (or strips if you prefer that). Place on the bottom of a 6-quart slow cooker, along with the onion and bell peppers.
2. In a medium-size bowl, combine 1 cup beef broth, soy sauce, brown sugar, ginger and garlic powder. Pour over the steak in the slow cooker.
3. Whisk together the remaining 1/2 cup beef broth with the cornstarch; pour into the slow cooker. Stir everything to fully incorporate all ingredients.
4. Place lid on slow cooker and cook on low for 5 hours. Taste just before serving, and adjust seasoning, if necessary.
