Preheat the oven to 450°F (232°C). Thoroughly mist a baking dish with cooking spray to help prevent the turkey from adhering during roasting.

Place the softened butter in a bowl with the garlic, sage, rosemary, thyme, parsley, salt, and black pepper. Mix until the herbs and seasonings are evenly dispersed throughout the butter.

Carefully separate the skin from the turkey breast meat while keeping the skin attached. Spread approximately half of the herb butter directly over the meat beneath the loosened skin.

Distribute the remaining herb butter evenly across the outside of the turkey skin.

Set the seasoned turkey breast into the prepared baking dish. Roast at 450°F (232°C) for 15–20 minutes, stopping when the skin begins to develop a golden-brown color.

Reduce the oven temperature to 350°F (177°C). Continue roasting for approximately 1 hour and 15 minutes, occasionally spooning the accumulated pan juices over the turkey.

Begin checking the internal temperature after roughly 1 hour. Insert a meat thermometer into the thickest portion of the breast without resting it against the bone.

Remove the turkey from the oven once the internal temperature reaches at least 160°F (71°C).

Loosely cover the roasted turkey breast with foil and allow it to rest for 5–10 minutes, or until the internal temperature reaches at least 165°F (74°C). Resting allows the juices to redistribute throughout the meat before carving.

Transfer the rested turkey breast to a serving platter. Add fresh rosemary sprigs as a garnish, if desired, then carve the turkey into slices and serve.