In a cast iron griddle (I love using the griddle because it chars the asparagus without having to light up the grill) melt about 2 tablespoons of butter. Add the asparagus (cut the ends of the asparagus is too long to fit in the pan) and cook over medium heat. Toss frequently to ensure it chars evenly on all sides. The asparagus is done when you can pierce it with a fork, about 5-10 minutes depending on how “done” you like your asparagus.
Add the Miso and softened butter to a bowl and mix to fully incorporate the ingredients. It should be smooth and not lumpy. I find using a whisk or electric beater yields the best result.
When the asparagus is finished, put on a platter with large dollops of the miso butter. If you feel so inclined, add some chopped herbs (tarragon, parsley or cilantro would work great!).