Slice the beef top sirloin steak into thin strips. This helps the beef cook quickly and evenly, ensuring it remains tender.
Step 2: Make the Marinade
In a bowl, combine soy sauce, white sugar, cornstarch, and ground ginger. Mix well to create a marinade.
Marinate the sliced beef in the prepared marinade for about 15-20 minutes. This step infuses the beef with flavor and helps tenderize it.
Step 3: Cook the Beef
Heat 2 tablespoons of vegetable oil in a large skillet or wok over medium-high heat.
Add the marinated beef to the skillet and stir-fry until it’s cooked to your preferred level of doneness. Remove the beef from the skillet and set it aside.
Step 4: Cook the Vegetables
In the same skillet, add the remaining 1 tablespoon of vegetable oil.
Add the sliced or diced onion and stir-fry until it’s translucent and slightly caramelized. The onions add a sweet and aromatic flavor to the dish.
Add the bell pepper to the skillet and stir-fry for a few minutes until they’re slightly tender yet still crisp. Using a mix of colorful bell peppers enhances the visual appeal of the dish.
Step 5: Combine and Serve
Return the cooked beef to the skillet and stir-fry briefly to combine it with the vegetables.
Pour any remaining marinade over the beef and vegetables. Stir-fry for an additional minute until the sauce thickens and coats the ingredients.
Once everything is heated through and well-coated with the sauce, remove the skillet from the heat.
