Add the water and rice (don't rinse it) to your instant pot, along with the mushroom seasoning powder, dried shiitake mushroom, and fresh ginger. Pressure cook on high, sealed, for 30 minutes. Allow the pressure to release naturally.
Remove the ginger and throw it away. Remove the mushroom and set it aside to cool for a few minutes. Then cut the stem off with scissors (bin it) and dice the mushroom into cubes.
You can use a stick blender to blend the congee if you like a really smooth texture.
Add the mushrooms back into the pot, along with the chicken and asparagus. Pop the lid back on your instant pot and cook for one more minute on high pressure. When the seal releases naturally, the congee is ready to eat.
Serve with a dash of white pepper and spring onions, if using.