1. Melt the butter in a heavy bottomed pot over medium heat. Add the onion, garlic, and ginger and cook, stirring often, until onions turn golden brown, about 10 minutes. Add the carrots and stir until well combined. Add just enough water or chicken broth to barely cover the carrots, about 2 cups. Cover the pot and cook until carrots are just tender when pierced with the tip of a small knife, about 30 minutes.

2. Working in batches, puree the carrot mixture a blender or food processor. Return the puree to the pot over medium heat. Add the miso and stir until it dissolves. Stir in the sesame oil, sugar, and season to taste with salt and pepper. Cook until heated through.

3. Divide the soup between four soup bowls and garnish each with some of the chives.