Very lightly adapted from Martha Stewart Living's One Pot. The technique here is the thing; the flavors can go in any direction. Swap out the Asian flavors for more traditional aromatics, if that's what you have. Serve it this way or use the meat in tacos, or salads, or sandwiches, or whatever; and then save the broth for something else. Or serve it this way and add egg noodles. On cooking times: Slow cookers vary wildly in how slow (or fast) they cook. One Pot recommends cooking on high for 2 hours, or low for 4 hours; my 4-pound-plus chicken took almost three hours on high to reach 165 degrees. So don't go by the cooking times; rely on an instant-read thermometer. —Nicholas Day
In a 5- to 6-quart slow cooker—a smaller slow cooker will be too small—place two bunches of scallions and half the cilantro on the bottom. Then place the chicken on top, breast up. Add the celery, mushrooms, ginger, star anise, peppercorns, and salt. Then add the water, adding more if the chicken isn't covered (or almost covered). Cook on high for 2 to 3 hours (or on low for 4 or more hours), or until the chicken reaches 165 degrees.
When the chicken is cooked, carve it into portions and divide it among the bowls. Divide the mushrooms among the bowls, too. Strain the broth and ladle it over the chicken and the mushrooms. Coarsely chop the remaining cilantro and scallions and sprinkle them over each bowl. Serve.