1. Preset the oven temperature to 350 degrees.
2. Whisk together the lemon juice, thyme, sage, pepper and salt.
3. Baste the turkey breast on all sides with the mixture.
4. Pour the broth into a roasting pan and place the turkey into the broth.
5. Bake the turkey for 1 1/2 hours, being sure to baste often with the juices.
6. Remove the turkey and allow to stand 5 minutes before carving. Then, slice thin.
7. Spread the slices of bread with the mayonnaise.
8. Add 2 to 3 slices of turkey and a lettuce leaf to the 4 slices of bread, forming the bottoms.
9. Top the sandwiches with the remaining 4 slices of bread.