The pre-dinner cocktail once had cachet in the restaurant world, but then came hard times. Diners began looking at it, meal-wise, as something of a gauche cousin to wine. But the cocktail is back in a big way as folks rediscover its role as stimulating foreplay to a sensual dining experience. These days, you're liable to find behind your favorite bar a master mixologist — part scientist, part artist, part spirit sommelier. At Area 31, you can enjoy a professionally muddled "St. Rosemary," made from Plymouth gin, St. Germain elderflower liqueur, apple juice, and rosemary. Meat Market offers a "Martini de Chèvre," goat cheese-infused vodka shaken with lemongrass, pink and black peppercorns, fennel, and Martini & Rossi dry vermouth — plus a blue-cheese-stuffed olive as garnish. Sra. Martinez serves a "Matador" of Skyy vodka, fresh strawberries, basil, jalapeño syrup, and a twist of lime. Old classics such as the sidecar and Tom Collins are also enjoying a resurgent popularity. These are the same elixirs that ushered in the cocktail lounges of the 1930s — not coincidentally, the last time we all needed a drink this badly.