Roast chicken and stuffing is the festive reading of the chicken sandwich, and the lead is the stuffing, not the bird. A slab of sage-and-onion stuffing, herby, oniony, faintly fatty, and densely savoury, goes in against cold roast chicken and immediately becomes the dominant flavour and the structural spine of the sandwich. Cold chicken on its own is mild and slightly dry; the stuffing supplies the seasoning, the moisture-binding starch, and the herb note the meat lacks, and it is the part that makes this read as a roast-dinner sandwich rather than a plain chicken one. The chicken brings the protein and the body; the stuffing is what gives it its name and its character.
The craft is moisture and ballast around a meat that has little to give. Roast chicken gone cold is lean and dries between bread, so it is sliced thin or torn and, crucially, never asked to carry the sandwich alone. The stuffing is the structural ally as much as the flavour: a sage-and-onion slab holds its shape, adds back the fat and salt the bird lost, and stops the filling reading as dry. It works best in a firm layer rather than crumbled loose, so it braces the chicken instead of scattering, and a thin smear of mayonnaise or a stripe of cranberry can sit alongside it for the lubrication and the sharp counter the gravy gave on the plate. The bread needs real structure for a heavy two-part filling, a sturdy white or a bloomer, and butter to the edges seals the crumb so the sandwich survives the gap before it is eaten.
The variations are the festive plate in order. A stripe of cranberry turns it toward the full Christmas reading; bread sauce pushes it further into roast-dinner territory; crisp bacon adds a smoky, salty edge. The same stuffing with turkey instead of chicken is the seasonal version, plain roast chicken the baseline, and chicken and mayonnaise the bound everyday default. Each deserves its own article rather than being crowded in here.