Prepare the beef by slicing it thinly against the grain.
Mix the soy sauce, oyster sauce, brown sugar, garlic, and ginger in a bowl to create the sauce.
Heat vegetable oil in a large skillet over medium-high heat.
Add the sliced beef to the skillet and cook until browned, about 3-4 minutes.
Remove the beef from the skillet and set it aside.
In the same skillet, add the shredded cabbage and stir-fry for 2-3 minutes until slightly wilted.
Return the beef to the skillet and pour the prepared sauce over the mixture.
Cook for an additional 2-3 minutes until the sauce thickens slightly and everything is well combined.
Garnish with chopped green onions and serve hot.