We rarely pass up dessert. Thus, our frustration that the treat we most crave isn't on a regular menu. In January, Ian Kleinman, the mad scientist chef behind the Inventing Room's molecular gastronomy eats, brought back his doughnut pop-up shop, a four-day special event at Bittersweet (held once before at Table 6). We devoured made-to-order, sugar-flaked, velvety doughnuts topped with a smorgasbord of treats (think chocolate Pop Rocks and exploding whipped cream)-and couldn't stop. Peanut butter and jelly. Bananas Foster. Lemon curd brûlée. Now we just have to wait until the shop pops up again: July 17 to 20 at Biker Jim's from 6 to 10 a.m.