Preheat the oven to 325 degrees F. In a small bowl, combine the softened butter, rosemary, garlic, sage, dried mustard, orange zest, salt, and pepper. Carefully lift the skin from the turkey breast and rub half of the seasoned butter directly onto the breast. Rub the rest of the seasoned butter on the skin. Season the turkey breast generously with salt, and pepper. Scatter the vegetables on the bottom of a roasting pan just large enough to hold the turkey. Set the meat breast-side up in the pan. Roast for about 2 hours or until an instant-read thermometer inserted into the thickest part of the breast registers 160 degrees F. Transfer the turkey to a cutting board and tent loosely with foil for 20 minutes. Carve the breast and serve with the pan juices. Reserve the leftovers for oven-roasted turkey sandwiches.
The turkey breast temperature will continue to rise as it rests.