Enter the Comfort Zone at 606 R&D

The mussels are small and wild, jimmied off the Hampton Bays where they cling together against the shore. They are scrubbed clean and steamed in a broth that tastes of green pastures slapped by cold waters, of Mont Saint-Michel’s salted grass and butter. Mussels, man. Since when did the little buggers hold so much flavor?

Sure, you must work for it, breaking apart hinged shells and scooping up the bright, salty liquor of cilantro, parsley, dill, and spinach. But there are slices of neatly grill-marked bread from Grandaisy Bakery to help you along, crisp on one side, soft on the other. Use your hands, make a mess. Keep in mind that Brooklyn’s 606 R&D is a restaurant best enjoyed with the sort of people who tell you when there’s something in your teeth.

In January, Ilene Rosen and Sara Dima transformed a hair salon on Vanderbilt Avenue into this restaurant, cleaning up the neglected knotweed plot out back to make it a chic deck of hanging bulbs and tables covered in butcher paper, set reasonably apart. Inside is as pretty and comfortable as a friend’s living room, with pale throw cushions and fresh wildflowers in glass bottles. Rosen cooks rustic, offbeat food in the narrow open kitchen while Dima runs a friendly, casual dining room that can feel like home. “I think my ponytail is caught in this tree,” said the waitress to the table next to mine. “Help?” It was. And they did. Service can be slow, but the waitstaff keeps it real.

The food here comforts. Often, it’s what you’d consider making for an impromptu dinner party: half a golden rotisserie chicken ($20) served with a bowl of yogurt, some spicy watercress, and toast. There is no wrong way to go taking this apart, but the best might be with a friend and a cold old-fashioned, sitting outside on the last warm evening of the year. A spiral of spicy pork sausage from Faicco’s is a real winner, served with a hefty, miscellaneous bread salad ($16), soaked in a well-seasoned dressing and tomato juice, scattered with basil. It is lovely.

There are eccentricities on the menu, too, which didn’t always please my dining companions, like the liver-filled celery ribs ($10), hippie-mom pancakes made with shredded carrots and parsnips ($16), and a nose-tickling sandwich of white bread, fluffy drained horseradish, and Benton’s bacon ($9). They might not be crowd-pleasers, but these oddities are what make 606 special, and I wouldn’t mind that fine, funny sandwich nicknamed “the horse and pig” wrapped up and delivered to me on a regular basis.

An ideal way to end a meal at 606 is with a pot of lemon-myrtle tea and a slice of hot plum pie with its crisp, latticed crust and gently sweet filling. Out on the patio, there’s the sound of water running. A book club pretends to meet about a novel, but ends up drinking wine and talking about having babies. A man kisses his partner on the wrist when he arrives to the table and nudges forward a tiny ramekin of radish wedges and soft, salty butter (that’s amuse-bouche for I love you).

On Sundays, things are a little different at 606. The only option is a no-nonsense set menu ($20), which might start with wee sandwiches of fried, sweet Delicata squash with aioli, or cocktail franks with mustard. But after this, it is always the same: a pure, deeply milky macaroni and cheese with a dark and crunchy top, huge salad leaves kissed with good olive oil, and roast chicken cut to pieces. On Sundays, everything is served family style. Much like at home, the goal now is to feed a large crew, rather than impress them. The Sunday chicken can be dry and flat, and it comes without the fixings you’ll find the rest of the week, but how it pleases the regulars—children whining in French, parents clinking glasses of $8 cocktails as the sky darkens, groups of friends from the neighborhood already dreading their Monday commute out of Prospect Heights. “I heard it’s supposed to rain tomorrow,” one of them says, sighing.

Dessert softens everything: a plate piled high with tender cake doughnuts in powdered sugar, cinnamon sugar, or best of all just plain, browned in the robotic countertop fryer, and served warm. They’re not greasy, and though they taste of the last sweet moments of the weekend, you can walk in and buy them on Monday morning, too.