Ten years in, Southeast Hawthorne Boulevard's only successful fine-dining venture has dramatically reinvented itself, under the leadership of lauded chef Matt Lightner, in a transformation no less surprising than, say, the phrase "Senator Al Franken." The restaurant that once specialized in enormous pork chops and bright fried vegetables is now the stage for bold culinary experimentation of a sort we've rarely seen in this city.

Lightner, who labored at the renowned restaurants Mugaritz (in Spain) and Noma (in Copenhagen), is working in a different vein from the tongue-in-cheek deconstructionists who've attracted so much attention. This isn't better eating through chemistry; most of his preparations could be replicated at home, if you were willing to spend a lot of time at it. Rather, Castagna's menu is filled with the sort of food a child might prepare, if that child happened to be a fantastically skilled cook—strange, evocative and occasionally off-putting in appearance, but very tasty nonetheless.

A few examples, which certainly won't be on the menu by the time you read this: thick slices of quick-pickled cucumber marinated in rice vinegar and dill, sprinkled with flowers and peeled green almonds, attacked from the side by an avalanche of snowy powder—actually frozen, shaved, smoked tuna—that looked like some sort of accident and tasted like some sort of sushi ($14); a dish of morel mushrooms, buckwheat groats, ferns and barbecued lamb that looked and smelled like a forest floor ($23); a carrot, poached in birch-wood syrup, coated with finely chopped bone marrow and hazelnuts, that tasted like a barbecued pork rib ($14); an aged loin strip steak ($30) that tasted grilled not because it had ever seen smoke, but because it was rubbed with garlic ash (slightly gritty, but not unpleasant). Even a relatively traditional appetizer of grilled shallots and squid arms in pan jus ($15) was presented as a terrifying Lovecraftian landscape. As I ate, I imagined Lightner grinning as he positioned the tentacles just so. Why serve chanterelles over a gelatinous rectangle of corn curd? Why not?

Desserts (all $10) are similarly playful. Roasted peaches are served with almond sorbet molded into the shape of peach pits, chocolate cake and cherries come smashed in a pile and øllebrod—a strange, chewy Danish confection of rye bread and beer—is rolled in chocolate and surrounded with green cake and berries in a tableau resembling a fallen tree.

None of these preparations can be inferred from the menu, which irritatingly only lists ingredients ("Herbs, Dungeness crab, seaweed, herb infusion, coriander, $16") in four numbered categories without further explanation, so don't hesitate to interrogate your waiter about the evening's offerings. He or she won't mind—Castagna's service is as efficient and friendly as ever. They know how "Bison" and "Red Fruit" are prepared, what "brown butter dashi" is and which of bartender David Cooper's slightly skewed cocktails (e.g., an "Autumn Sazerac" composed of absinthe dropped over a sugar cube in an empty single old-fashioned glass that's then filled with room-temperature rye whiskey and bitters) will best accompany your dessert.

So lovely is Lightner's plating, and so strange are his preparations, that dinner at Castagna can feel like too much. Thank goodness for the sparse decor; any further embellishment would be overwhelming. The wonders on the plate hoard diners' attention, which has the unfortunate effect of sucking the fun out of the room. I enjoyed every bite I tasted at Castagna, but I wish the place were a little more lively. The restaurant was half empty and near silent on the evening of my last visit, allowing the noise of the packed Cafe Castagna next door to bleed through the wall. I know I ate better than those raucous diners, but I envied them their din.

Castagna,