Sauté. Heat 1 tablespoon of oil in a large stockpot over medium-high heat. Add the mushrooms and sauté, stirring occasionally, until browned. Add the remaining 1 tablespoon oil, garlic and ginger. Sauté for 1-2 more minutes, stirring occasionally, until fragrant. Simmer. Add the vegetable broth and soy sauce and stir to combine. Continue heating until the broth reaches a boil. Add the frozen potstickers, half of the scallions, bok choy and stir to combine. Cook for 3-4 minutes or until the potstickers are cooked. Stir in the sesame oil and a few twists of freshly-ground black pepper. Taste and season with additional soy sauce or black pepper if needed. Serve. Serve immediately, generously garnished with the remaining scallions and any extra toppings that sound good.