This River North shop from the owner of Gilt Bar will sell just one thing: rich, artisan doughnuts. Options include old-fashioned buttermilk doughnuts, gingerbread cake doughnuts and oversized glazed doughnuts in chocolate, vanilla and chestnut flavors. We also hear that gourmet varieties such as carrot cake, lemon chiffon and maple-bourbon-bacon are in the works. Located in a former vault, the brick- and tile-adorned eatery won't operate under set hours; the shop plans to open sporadically and close when its stock, served warm and freshly glazed, is sold out. (Count on its Facebook or Twitter pages for more info). Order at the walk-up window or down your doughnut while standing at the eatery's singular table. In summer, an outdoor area seats 20.