When a beloved, acclaimed restaurant closes, its shoes can be hard to fill. Such is the case with the late, lamented French eatery Radius, which shuttered its Financial District space at 10 High St. in 2013. What better way to re-christen the address than by opening a brand-new location for a renowned franchise that already has a rabid following? Such is the case with New York transplant Serafina Boston (serafinaboston.com). Offering light Italian fare and its signature thin-crust pizzas, Serafina has grown from its first location, opened in 1995, to more than 20 outposts in New York, Philadelphia and worldwide. The Hub version not only boasts crispy pies featuring homemade tomato sauce, but also plenty of freshly made pasta and seafood dishes, all served in a Tuscan-inspired atmosphere.