Heat oil in a large sauté pan to high heat and sear the turkey breast on each side. Preheat oven to 325 degrees.
In a roasting pan add the carrots celery and onion to the bottom of the pan; add the turkey on top of the vegetables.
Cover pan with foil and roast turkey for 1 ½ - 2 hours or until the internal temp is 180 degrees- 10 minutes before the turkey is done rub the turkey with the herb mixture and bake.
Let rest for 10 minutes before you carve it.
Chop all the herbs. Using a mixing bowl add the herb mixture. Then stir.
For the Gravy:
In a pot, heat liquid to a simmer. Add the remainder of the ingredients except for the cornstarch slurry. Simmer for 10 minutes on low heat, just long enough to cook the vegetables but not reduce the liquid.
Make the cornstarch slurry by mixing the cornstarch and 2 T. of water together, then whisk into the gravy to thicken.