Rick Bayless is forever foraging in remote nooks of Mexico and in the kitchens of its most creative chefs to bring back incomparable new dishes to the most ambitious of his three restaurants on this busy corner. Lately, a Baja chef inspired him to offer olive-wood-smoked quail with homemade duck prosciutto. Spurred by a Mexico City chef, he offered octopus and squid in aspic with molecular-cuisine-style beads of squid ink and tomato. Yet there are always classics, like aged prime rib eye in Oaxacan black mole. The delight progresses to a frozen peanut parfait with bittersweet chocolate sauce, ground cherry compote, and candied chicharrón. Smooth service; intriguing wines and tequilas.