Chop all the vegetables into bite size.
Cut beef into bite size as well.
Add black pepper, more or less to your taste, 1/2 tsp starch water, and seasoning sauce. Let it sit to marinate.
Sauté the vegetables with salt and pepper in a pan starting with the hardest ones like onions and bell pepper.
Once the vegetables are sautéed, remove from the pan and set aside.
Cook the beef on the same pan used for vegetables. Add a lot of black pepper to enhance the spicy taste. When the meat is cooked half way through, add oyster sauce and cooked vegetables.
Thicken the dish by adding starch water.
Garnish with toasted sesame seeds and enjoy!