Michael McKean has signed to star in “Superior Donuts,” the new play from Pulitzer-winning “August: Osage County” scribe Tracy Letts, beginning performances at Chicago’s Steppenwolf Theater Company on June 19 for a June 29 opening.McKean currently is appearing in the Broadway revival of “The Homecoming,” which ends its run Sunday. New play follows the relationship between Arthur Przybyszewski (McKean), the owner of a donut shop in the Uptown neighborhood of Chicago, and his sole employee, Franco Wicks (Jon Hill), a black teenager who wants to change the shop for the better. Cast also includes Steppenwolf ensemble members Yasen Peyankov and James Vincent Meredith, with Tina Landau directing. Letts’ “August: Osage County” premiered at Steppenwolf before transferring to Broadway. The hit production closes April 20 at the Imperial, reopening a week later in its new home at the Music Box.