For his first post-Myth venture, chef Sean O’Brien will be returning to his former Jackson Square stomping ground for Zinnia, located in the old Scott Howard space. Hoping to open sometime after October, O’Brien plans to craft a globally inspired New American menu similar to the one at Myth but with a larger selection of handmade fresh pastas; he’ll also be instituting his popular half-portion option for many of the dishes. The dining room will include a semiprivate chefs table for 10, a communal table and a bar that will serve the full menu (500 Jackson St.).