To create a Slow Cooker Salisbury Steak that is gluten-free you just need to make a swap. Instead of using Panko bread crumbs, for the beef patties choose certified gluten-free Panko crumbs or breadcrumbs made from gluten-free grains like rice or corn. Also make sure that the brown gravy mix you use is labeled as gluten-free because some commercial mixes might have thickeners that contain gluten. These straightforward substitutions guarantee that everyone, at the table can relish this dish without any uneasiness.