Preheat oven to 325℉. Place the turkey breast on a rack in a roasting pan, skin side up.
In a small bowl, combine the olive oil, garlic, lemon juice, mustard, rosemary, sage, thyme, salt, and pepper. Use your fingers to slowly separate the skin from the muscle by moving two fingers in between in a sweeping motion. Add half of the herb mixture underneath the skin on both sides, and then rub the remainder of the mixture evenly all over the surface.
Pour the wine into the bottom of the roasting pan.
Roast the turkey for 1 hour and 45 minutes, until the skin is golden brown and an instant-read thermometer reads 165℉ when inserted into the thickest and meatiest part of the breast.
Once removed from the oven, cover with tin foil and let rest at room temperature for 15 minutes.
Meanwhile, with a fork, combine the butter and flour in a bowl. In a separate saucepan, add the drippings from the pan and the chicken stock. Bring to a boil.
Add the butter and flour mixture to the saucepan slowly, using as much as needed until gravy begins to thicken. Turn the heat down to a low simmer. Add salt and pepper to taste.
Slice your turkey breast and serve warm with gravy!