Preheat oven to 350..Whisk the olive oil with the chopped rosemary,garlic,salt,pepper,lemon zest and juice. Halve the mixture..Carefully loosen the turkey skin with your fingers on the breast area.rub in half of the oil mix
sandwich 2 slices of cheese and leaves from sprig of rosemary between 2 slices of the prosciutto..repeat on other side of the breast..Slide the prociutto sandwiches under the loosened skin to cover the turkey breast on both sides
Rub turkey all over with remaining oil mixture..add some to the cavity as well.. You can stuff at this time..but I do not..Roast on a roasting rack in a roasting pan for 30 min..turn the heat down to 300 degrees..Roast for 3 hours, basting every 30 min..or until a thermometer reads 180 degrees..in the inner thigh area..To make a juicier turkey put a pan of plain water in oven as well..
Prepare the gravy while turkey is resting..tented with foil, on a carving board..Pour off the excess oil in the roasting pan, leaving the brown drippings..Set the roasting pan on the stove over med heat. Whisk 2 cups chicken broth with the cornstarch.and pour into pan, stirring, Bring to boil; cook five minutes or until you reach your desired thickness..Strain into gravy boat..(because of your rosemary) and keep warm