Linton Hopkins’ Slow-Cooked Collards with Mustard Potlikker

Clean, de-stem, and cut collard greens into wide strips. In a large, heavy pot, add sorghum and vinegar and bring to a low boil. Add fatback (or bacon) and onion and cook, stirring, for 2 to 3 minutes. Add greens, chicken stock, and cayenne pepper. Season to taste with salt and pepper. Toss thoroughly and simmer gently for 30 to 45 minutes, stirring occasionally, until very tender. Before serving, drain the potlikker from the collards and whisk in the whole-grain mustard. (Reheat the potlikker on medium-low heat before serving, if necessary.)