NOT SINCE IVAR HAGLUND and Victor Rosellini opened their legendary fried-clam Alfredo bar, Ivarini’s, have two Seattle restaurant legends collaborated so winningly. (No wait . . . we dreamt that.) In their shared occupation of the historic brick Kolstrand building at Ballard Ave’s ragged gateway to Frelard, Ethan Stowell (Tavolàta, How to Cook a Wolf, and Anchovies and Olives) and Renee Erickson (she of the stunning Boat Street Café and adjacent Boat Street Kitchen) aren’t collaborating so much as symbiotically thriving, in a single space cleaved in two by a wall of glass. In the pristine whitewashed back room is The Walrus and the Carpenter —you can smell the sea from the patio!—Erickson spotlights oysters with champagne mignonettes and elegant French noshes, meant to be savored with something off her careful wine list or cocktail card. Raw brick and dark lights dominate at Staple and Fancy Mercantile on the side fronting Ballard Avenue. There, Stowell—happy to be back on the line in the open kitchen—presents more substantive pastas, meats, fish, and chef’s-choice four-course meals. Both just opened as we went to press—we can’t yet vouch for the food—but we already dig the yin-yang of the mood.