Some friends and I have an occasional "mom's night out", usually in Cambridge, sometimes in Arlington, and are continually frustrated by our attempts to find a place for coffee and dessert open after 9. We used to go frequently to Tea Tray in the Sky in Porter Sq. but have not been at all happy with it's successor. We shun Starbucks if possible. We're not looking for super high-end, but we want more than just chocolate chip cookies or ice cream. Someplace comfy to sit for a while, open till 10 or later, with yummy, fairly sophisticated and varied dessert offerings. Any ideas?