Place chicken breasts between two layers of plastic wrap and pound to an even half-inch thickness. Lightly score the surface to ensure even cooking, then season with salt and pepper.

Create a breading station: one bowl for flour, one for eggs whisked with water, and one for panko. Dredge chicken in flour, dip into egg, and press firmly into panko crumbs.

In a heavy skillet, heat a quarter-inch of oil over medium-high heat. Fry cutlets in batches until deep golden brown and cooked through, approximately 4–6 minutes per side.

Combine Worcestershire, ketchup, soy sauce, and sugar in a small pot. Simmer until reduced by about one-third, then whisk in the mustard and allspice.

Serve the crispy cutlets atop a bed of fresh, finely shredded cabbage with the sauce drizzled over or on the side.