In a food processor, process ham until minced or ground. Transfer to a medium bowl; add mayonnaise, mustard and pistachios. Mix well; set aside. Rinse spinach in cold water. Cook in a large skillet with only water clinging to the leaves until limp; drain.
In a food processor, process spinach, cream cheese, milk and dill until smooth; set aside. Cut bread in half lengthwise; hollow out top and bottom, leaving a 1/2-in. shell. (Discard removed bread or save for another use.) Spread spinach mixture inside top and bottom halves of bread. Pack ham mixture into bottom half, mounding slightly. Replace bread top and wrap tightly with foil. Chill for at least 2 hours.