Melt butter in a small saucepan over medium heat, then add the green onion and garlic and cook until fragrant and soft.
Add in black soybeans, chicken bone broth, chili powder, cumin, cayenne pepper, and salt and pepper. Increase heat to high and bring the pot to a boil, then reduce heat to medium-low and let simmer until most of the liquid has cooked off, about 7-10 minutes.
