We were surprised to find such an upscale eatery in little old Mount Vernon, but chef Enam Chowdhury has worked such magic that visiting Dallasites are combining antiques treasure hunts with dining at the Chophouse. We began with the jumbo lump crab cakes, pan-seared and served with whole-grain mustard, along with the C.O.B. Caesar Salad, a nontraditional but remarkable combination of romaine, roasted garlic chips, Parmigiano Reggiano, and roasted sweet peppers. Continuing in the aquatic vein, we relished our shrimp and grits (Anson Mills variety) and lobster mac and cheese, studded with Maine lobster, bathed in Mornay sauce, and topped with toasted panko.