The menu at The Black Labrador (4100 Montrose, 713-529-1199) has a quaint description of the British comfort food known as bubble and squeak ($7.50). It says the dish gets its name from the sounds the ingredients make while cooking. But any British schoolboy will tell you what bubble and squeak really means. It's the sound your stomach -- and other body parts -- emit as they digest a meal of cabbage and potatoes. Originally, bubble and squeak was made with leftover Sunday roast to which various vegetables, but always potatoes, were added. Over time, the dish turned vegetarian with the omission of the meat. At the Black Lab they take mashed potatoes and combine them with onions and cabbage and make small flat cakes out of the mixture. These are then fried in olive oil until both sides turn dark brown. Like much traditional British food, they taste fairly bland. That's why they're served with a wow-wow sauce, an early-18th-century condiment made of vinegar, Worcestershire sauce, mustard and broth that imparts a little zest.