Whisk stock, miso, kimchi juice, and black bean paste in a small saucepan or medium microwave-safe container. Bring to a boil over high heat or in a microwave oven on high.
Place ramen, chicken, kimchi, and mushrooms in a medium bowl. Pour broth over and let sit 5 minutes, stirring once to loosen noodles. Top with scallions, mint, and sesame seeds. Do ahead: Broth can be made 1 day ahead. Cover and chill. Editor’s note: This recipe was originally published in May 2016 as part of an office lunch series. Head this way for more of our easiest soup recipes →
