Marinate Chicken: In a bowl, mix chicken thighs with light soy sauce, dark soy sauce, oyster sauce, sesame oil, garlic, ginger, sugar, and white pepper. Let marinate for 20–30 minutes.
Rinse the Rice: Rinse jasmine rice under cold water until the water is clear. Drain well.
Assemble in Rice Cooker: Add rice and chicken broth to the cooker. Gently layer the marinated chicken, Chinese sausage, and mushrooms on top. Do not stir.
Cook: Set the rice cooker to the “White Rice” or “Cook” setting. Let it run the full cycle.
Rest: Once cooked, leave it on "Keep Warm" for 10 minutes to let it finish steaming.
Finish and Serve: Fluff the rice and mix gently. Garnish with scallions. Optionally, drizzle with a soy sauce mixture before serving.