Turn burner on stove to medium-low heat
In a non-stick pan, melt butter and add miso and water. Mix until emulsified.
Add more water until it covers the bottom of the pan.
Add halved brussels face down in the pan
Raise heat to medium.
Cover pan with lid for 5 minutes or until sprouts start to get tender.
Uncover and turn heat to medium-high.
Lift and place down each sprout to ensure miso sauce covers the bottom.
Cook until bottom caramelizes.
Serve.