UpStairs on the Square so enjoyed Restaurant Week that they’re extending their special prix fixe menus indefinitely. Enjoy lunch in the Monday Club Monday through Saturday for $20 per person, or come in for dinner Monday through Thursday for $30 per person. Chef Susan Regis’ menu features a pithivier of roquefort with spicy summer greens; thyme roasted duck roulade with concord grape and melting leeks; and maple sugar tart with fromage blanc ice cream. Upstairs in the Soiree Room, chef Amanda Lydon will be offering a $40 prix fixe menu featuring dishes like fish soup with red pepper aioli and toasted croutons; duck breast with mustard greens and orange; and mousse au chocolat. The menus for September, which will change on a weekly basis, honor Julia Child and Mastering the Art of French Cooking. Call UpStairs on the Square for reservations at 617.864.1933.