Bring a small pot of water to a boil to parboil the beef. Drop the beef in the simmering water, then stir to break up any chunks. Let simmer for 1 minute, then drain.
To a large clean pot, add crushed ginger, diced tofu, diced mushrooms, the reserved mushroom broth, and 10 cups of water.
1 large knob ginger, 10 cups low-sodium chicken broth
Season with salt and chicken bouillon. The seasoning here will give the tofu and mushrooms more flavor. Bring the soup to a boil.
1.5 tsp salt, 1.5 tsp chicken bouillon powder
Once the soup is boiling, lower it to a simmer. Add the beef, and stir to break up any chunks.
As the soup simmers, skim off any foam on the surface.
In a bowl, mix the cornstarch slurry until fully dissolved.
5 tbsp cornstarch, 5 tbsp water
With the soup at a simmer, gradually add the cornstarch slurry while stirring the soup slowly. It should thicken almost immediately. If you prefer the soup to be thicker, you can add more cornstarch slurry.
Very lightly beat the egg whites, just to break up the large clumps. Do the same with the egg yolks. You don’t want to beat them too hard as they will form bubbles, which you don’t want in your soup.
Slowly drizzle in the egg whites to the soup while stirring slowly to create delicate ribbons. Repeat afterwards with the egg yolks.
Add the chopped cilantro and scallions, white pepper, and any additional seasoning to taste. Enjoy!
1/4 tsp white pepper