Slice the beef into ¼ of an inch thick pieces. I am using top sirlion today. Other tender cuts such as ribeye, flank steak, round steak, and beef chuck will also work. 

Thoroughly mix the beef with minced garlic, ginger, salt, ground black pepper, 1 medium-size egg, 2 tbsp of cornstarch, and 2 tbsp of freshly squeezed orange juice, which is one of my secrets. Not only does it give a nice fruity taste, but also the acid and the enzyme will tenderize the beef. Just be sure to use fresh orange juice. Long life product doesn’t have the enzyme anymore.

To make the Beijing beef sauce, combine all of the following ingredients thoroughly: 2 tbsp of soy sauce, 1 tbsp of oyster sauce, 1 tbsp of tianmian sauce, 1 tbsp of Chinese black vinegar, ¼ cup of brown sugar, 1.5 tbsp of honey, 1 tsp of dark soy sauce, 1 tbsp of cornstarch, 1 tbsp red chili flakes, and ⅓ cup of orange juice. If you look at the list of ingredients for the store-bought Beijing beef sauce (Panda Express brand), you will see that the first ingredient is water. Using orange juice is another secret to making this dish taste better than takeout because citrus fruit always pairs well with the sweet and sour taste.

Next, coat the beef with cornstarch. Spread some of the cornstarch in a container and put the beef slices in. Cover the beef with another layer of cornstarch and put on the lid. Then shake well. Eliminate the excess starch and set the beef aside to rest for 10 minutes so the starch has enough time to bond together. Otherwise, it will flake off while frying and ruin the quality of the oil.

Why add cornstarch to the marinade if you are coating the beef with cornstarch anyway? Well, the first 2 tbsp of cornstarch acts like glue, and it will catch more starch during coating, making a thicker breading.

Can you use all-purpose flour? The answer is yes, but all-purpose flour contains gluten, which makes the crispy coating soften fast. If you do so, please serve and enjoy the beef quickly before you lose the crispiness.

Heat 1 cup of oil in the wok to 400F, add the beef one by one, and fry over high heat for 1 minute per side or until both sides are golden brown. It is best to add the meat in a certain order so that when you flip the slices over, you can start with the first piece you put in.

Remove the beef to the side, use a sieve to skim all the cornstarch lumps, and continue to fry the next batch. You may need to fry all the meat in 2-3 batches, depending on the size of your cookware.

Once all the beef is done frying, pour most of the oil out and leave about 2 tbsp of oil in the wok.

Turn the heat to maximum and add the bell pepper and onion to the wok. Stir over high heat for a minute or 2. then remove the onion and bell pepper to the side.

Pour in the Beijing beef sauce. Stir over medium heat for a couple of minutes or until it is thickened.

Introduce the beef, bell pepper, and onion back to the wok. Toss thoroughly. Make sure every piece of the beef is coated with the sauce. Serve with white rice.