Lahmacun (pronounced "lah-ma-JUN"), a provincial Anatolian classic that could be described as a Turkish pizza, is as good an introduction to this world-class cuisine as any. The base is a thin wheat bread called pide (a delicate Turkish version of pita), which is topped with meat or vegetables, then baked briefly in a wood-fired oven; the combination summons up all the charms of ancient, rustic Mediterranean cooking in a single dish. The Istanbul Grill and Deli [5613 Morningside, (713)526-2800], the city's only purely Turkish restaurant, serves lahmacun as an appetizer ($2.49) or entrée ($6.99). The vegetarian version is topped with tomatoes and spicy peppers. The other is topped with tomatoes and lamb, with the animal slaughtered in the traditional hallal (Arabic for "lawful") method. The lamb, consequently, has an arresting flavor that is missing from the mainstream American variety.