To make the miso, place the miso, water and wasabi in a small bowl and whisk to combine. Set aside.
Place a large saucepan half-filled with water over high heat and bring to the boil. Line a large steamer with non-stick baking paper. Place the tofu and gai larn in the steamer and cover with a tight-fitting lid. Place the steamer on top of the saucepan and steam for 5 minutes or until the gai larn is tender. Place on plates and spoon over the miso to serve. Serves 2.