The menu at La Carta De Oaxaca is a blessedly simple document: just some tacos, a few small plates and appetizers, a couple of dinner plates (like the stewed lamb or chiles rellenos), and one soup. All told, there are fewer than 20 options for those wise enough to show up hungry, but the one that really matters is the posole. This highly traditional Mexican soup is one of the greatest gifts of the Latino canon?a hearty mix of pork and hominy in a rich broth, served with a few of La Carta de Oaxaca's homemade tortillas and a full spread of sides to customize your bowl. Sliced radishes, chopped onions, fresh cilantro, and shredded cabbage all await you, but even without any of these, the plain bowl is still one of the great miracles of rustic cookery, and one of the best bowls of soup served anywhere in the city. ?Jason Sheehan 5431 Ballard Ave. N.W., 782-8722