Prepare the beef: Cut beef into 1/4-inch strips against the grain. Season with salt and pepper. Optional: brown in a skillet with oil for 2-3 minutes per side for enhanced flavor.
Layer ingredients in crock pot: Place seasoned beef strips in the bottom of your slow cooker. Add sliced onions, then layer bell pepper strips on top.
Make the sauce: In a small bowl, whisk together soy sauce, beef broth, Worcestershire sauce, brown sugar, minced garlic, and ginger. Pour over the ingredients in the crock pot.
Cook low and slow: Cover and cook on LOW for 6-8 hours or HIGH for 3-4 hours, until beef is fork-tender and easily shreds.
Thicken the sauce: During the last 30 minutes of cooking, mix cornstarch and cold water in a small bowl to create a slurry. Stir into the crock pot and continue cooking until sauce thickens.
Final touches: Taste and adjust seasoning if needed. Remove bay leaf if used. Let rest for 5 minutes before serving.
Serve: Garnish with chopped green onions and serve over steamed rice, egg noodles, or mashed potatoes. Enjoy your perfectly tender pepper steak!
Chef's Tips: For best results, don't lift the lid during cooking as this releases heat and extends cooking time. Beef should reach an internal temperature of 190-200°F for optimal tenderness.