To make the dressing mix all of the dressing ingredients together in a bowl and whisk until it has emulsified I normally add these to a jar and shake)

Heat a frying pan with a lid for a couple of minutes until it starts to smoke. Add a few drops of sesame oil to the pan and swirl around. Add the bok choy to the pan and close the lid tightly. If your pan doesn’t have a lid, use a large pot lid to seal it. Shake the pan and allow it to cook for about 2 minutes. It generates its own steam. Add a splash of water, stir and cook for a bit longer if necessary, then set aside in a bowl. Repeat this with the mixed mushrooms and then toss this with the bok choy and the miso dressing.