Heat 1 tbls. of the peanut oil in a 12" skillet over medium high heat until they shimmer. Add the mushrooms and cook, stirring occasionally, until the mushrooms release their liquid, about 5 minutes.Increase the heat to high and cook, stirring occasionally, until the liquid has evaporated, about 8 minutes longer. Add the remaining peanut oil, reduce the heat to medium and continue to cook, stirring once every minute, until the mushrooms are dark brown, about 8 more minutes.
Add the sesame seeds and ginger and cook, stirring constantly, until the ginger is fragrant, about 30 seconds. Add the rice vinegar, sugar and soy sauce and cook, stirring constantly, until the liquid has evaporated, about 30 seconds. Remove from the heat and stir in the sesame oil. Move to a serving dish, sprinkle with the scallions, and serve. Enjoy!