Cut top one third off the loaf of bread and set aside. Scoop out some of the bread inside to form a “bread bowl”, leaving about 1 inch (2.5 cm) thick walls. Spread mayonnaise and the basil pesto on the inside surfaces of both the top and bottom of the loaf. Layer lettuce in the bottom, then top with sliced tomato, eggs, sun dried tomatoes (if using), olives, mozzarella cheese, onion and turkey breast, cover with the topof the loaf. Wrap the sandwich well with plastic wrap and place in the fridge. Place a large plate over the top of the sandwich and weigh it down with something heavy.
Cut into six wedges and serve.