Start by scraping the bottom of your slow cooker to remove any excess skin that may have fallen off or stuck to the bottom. Gather up ¼ cup of broth and whisk in 3 ½ tablespoons cornstarch and set aside. Next, heat a skillet over medium-high and pour in 2 ¾ cups chicken broth and the pan scrapings. Bring to a simmer then whisk cornstarch mixture into the pan and season with salt and pepper if needed. Continue cooking mixture and whisking constantly, until thickened, for about 1–2 minutes. For thicker gravy, you can add in a little heavy cream.