Season the ground beef with salt and pepper, mix well and set aside.
Squeeze as much water as possible out of the tofu and cut it into 1 inch cubes.
Peel the ginger with a spoon. Mince the ginger and garlic and place in a small bowl.
Remove the roots from the scallions, thinly slice the whites and place them in a bowl.
Slice the scallion greens on a bias and place in a separate bowl.
Brown the ground beef in a large pot over medium heat until it is cooked through and crispy. Reserve a couple tablespoons of the fat, drain the rest and set the beef aside.
In the same pot add the reserved beef fat and cook the scallion whites, ginger, and garlic until fragrant. Add the chili flakes, chilis, or doubanjiang at this point if you are using them.
Add the stock into the pot along with the tofu. Cover with a lid and bring to a simmer.
While the tofu is coming to a simmer mix the soy sauce, mirin, and black bean sauce in a small bowl. Also mix the cornstarch and water in another container.
Once the tofu has reached a simmer add in half of the ground beef and the sauce mixture and cook for 5-6 minutes.
After 5-6 minutes add half of the cornstarch slurry and stir it in. Then add the rest and stir in again. Allow that to cook for a couple minutes to thicken.
Add in the rest of the ground beef and remove from the heat.
Garnish with a drizzle of toasted sesame oil, the scallion greens, and white sesame seeds.
You can also top with some toasted crushed Szechuan peppercorns if you like.
Serve over steamed rice.