When all those gourmet burger–flippers, artisan pizza–bakers, and locavores on Mass Ave say their prayers at night, they should give a nice shout-out to Regina Mehallick. Chef-owner of the moody little 17-table R Bistro since she opened it in 2001, Mehallick was slow-braising Maple Leaf Farms duck legs and tossing local kale with mustard vinaigrette back when a couple of today’s hot young chefs were still in short pants. You can set your Day-Timer by the weekly rotation of her menus—so even her most popular dishes have an ephemeral quality. We fell in love with an early-winter bowl of bacon-and-beet soup, a chunky puree of sweet earthiness that left us with a serious craving. The same goes for a long-gone cider-glazed quail stuffed with bleu cheese and apples. And (hint, hint) we would welcome the return of sous chef Erin Kem’s sauerkraut soup with a ticker-tape parade down Mass Ave.