Since the war in Yemen began last year, getting permission to enter the country has become a complex process. A recent call to the country's embassy in D.C. was fruitless on the visa front but concluded with a recommendation: "You really must try Yemen Café, in Brooklyn. They have all the best Yemeni food there." The friendly advice of a diplomatic official is usually ignored to the detriment of the advisee, so a trip to Cobble Hill, on whose northern extremities the café perches, amid a cluster of Middle Eastern shops and restaurants, was soon conceived. Yemen Café has three rows of tables, at the end of which a television screen beams images of the owners' home country: green rolling hills, the majestic mosques and towers of Sana'a, a traditional dagger, or janbiya.