When the Pubbelly Boys open restaurants, they call them concepts. Their strategies, though, are not about location. It's not décor. Nor cuisine. Or even target crowd. The concept, rather, is Pubbelly. The word describes not food or ambiance, but brand. And PB Steak -- the latest South Beach restaurant to bear the insignia of Miami's fastest-growing restaurant empire -- is its most recent poster child. Since 2010, José Mendín, Andreas Schreiner, and Sergio Navarro -- known as the Pubbelly boys -- have opened six thriving restaurants in South Florida. Their monolith now sprawls from South Beach's Sunset Harbour to Alton Road to South Miami. Mendín, who was the executive chef at the original Pubbelly, runs the kitchen here. The concept is the same as at the other joints: small plates, fusion cuisine, and ingredient-centered fare. But like all triumphant steak houses, PB Steak offers more than slabs of dry-aged meat, baked potatoes, and mac 'n' cheese. It also proffers well-executed seafood dishes and pristine selections from a raw bar. The divergent options make for an enjoyable dinner that balances the decadence of a 26-ounce porterhouse with the vibrancy of a Kumamoto oyster.