Add rice to the rice cooker pot. Rinse and drain the rice until the water runs mostly clear.
Add water, chicken powder, soy sauce, mirin, shallots, and a drizzle of sesame oil. Mix until the seasonings are combined.
Place the sliced shiitake mushrooms evenly on top of the rice.
Cook the rice.
Once the rice is cooked, fluff with a rice paddle and mix the mushrooms throughout.
Top with sliced green onions.