The ultimate meatball sandwich

This really is the ultimate meatball sandwich: juicy pork and fennel meatballs, a rich tomato sauce, crunchy sweet fennel pickles and a nutty, dreamy pesto. My meatballs and tomato sauce are adapted from recipes in The Frankies Spuntino Kitchen Companion & Cooking Manual, the must-have cookbook from the two chefs behind the popular NYC Frankies Spuntino restaurants.