Mom says to first marinate the liver slices in dark soy sauce, cooking wine, ground white pepper to taste, maybe a little sesame oil. Then heat some cooking oil in a wok, fry chopped garlic and shredded ginger until fragrant, toss in the liver and stir fry briefly. Add green onions when nearly done. And yeah, just barely past pink is perfect, any longer and it's like gnawing on strips of rubber.