We arrived in London after an enjoyable flight with Virgin Atlantic, their Middle Class service providing us with spacious seats and a choice of four entrees for dinner. Our first stop was the Ritz Hotel on Piccadilly, a famed hostelry that justifies its enviable reputation. For dinner that evening, we walked into the heart of nearby Mayfair to Mulligan's, the first Irish restaurant and oyster bar in the West End. Declining to sample the 14 different Irish whiskeys, we discovered black velvet, an aptly named tipple combining draft Guinness with champagne, which effectively soothed away our jet-lag. The upstairs Oyster Bar serves a variety of Irish snacks, but we dined in the club-like restaurant on black pudding, crisp outside, well-spiced and moistly flavorful within; a bou ntiful omelette of wild mushrooms; pig's feet, the meat cut from the bone, breaded, and formed into balls; a thick, juicy cut of wild salmon; intensely flavored beef and oyster stew; and ox tongue in a madeira sauce served over mashed potatoes and cabbage . Homemade lemonade and traditional soda bread with Irish butter were simple yet perfect expressions of Irish cuisine, which relies on the natural tastes and flavors of its fresh ingredients. An Irish lemon tart, served waarm, a not