Heat a steamer with 1 inch of water, this can be your rice cooker with a steamer tray or a large pot with a trivet. Get out a heatproof plate that will fit either in your rice cooker or pot. If you have a steamer handles, get that out as well and place near the steamer.
Slice off the end of a tube of egg tofu, remove the piece from the end, then push out the tofu from the tube.
Slice the tofu into ½ inch slices and arrange on the heatproof plate.
Remove the stems from the Shiitake mushrooms and discard, thinly slice the mushrooms.
Cut off the root sections of the Shimeji and Enoki mushrooms and separate into individual stems.
Arrange the mushrooms on top of the egg tofu. Sprinkle with the sliced chilies is using.
Mix together the oyster sauce, soy sauce, sugar, sesame oil, and black pepper as desired. Pour over the mushrooms and egg tofu.
Place the plate in the heated steamer of your choice, cover, and steam for 10 minutes.
Carefully remove the dish from the steamer.
Sprinkle the sliced spring onion over the mushrooms and egg tofu.
Serve with rice or porridge on the side as a breakfast, lunch, or light dinner. Enjoy.