Heat an oven to 400 degrees F. (200 degrees C). Pat the turkey breast dry with paper towels.
Gently separate the skin from the meat with your fingers, enough to insert butter. Spread 1 tablespoon of softened butter under the skin.
In a small bowl, combine the remaining softened butter, olive oil, dried rosemary, salt, and black pepper. Stir until smooth.
Spread the herb butter mixture over the top of the turkey breast, ensuring even coverage and a flavorful crust.
Preheat your oven to 400°F (200°C). Place the turkey breast, skin-side up, in a roasting pan.
Roast for about 45–50 minutes, or until an instant-read thermometer in the thickest part reads 165°F (74°C). (If skin browns too quickly, loosely tent with foil.)
Remove the turkey from the oven and loosely tent with foil. Let it rest at least 15 minutes so the juices redistribute. Then slice across the grain and serve.
Notes
Pat the Turkey Dry: Removing surface moisture helps the skin crisp up beautifully as it roasts.
Loosen the Skin: Gently separate the skin from the meat before spreading butter underneath. This locks in moisture and infuses flavor directly into the meat.
Use Room Temperature Butter: Softened butter spreads more evenly, helping the skin brown evenly and preventing tearing.
Preheat the Oven Fully: Starting in a fully preheated oven ensures consistent roasting and even browning.
Monitor the Temperature: Use an instant-read thermometer and remove the turkey breast from the oven when it reaches 160°F. Let it rest, the temperature will rise to 165°F as it sits.
Rest Before Slicing: Allow the roasted turkey breast to rest for at least 15 minutes so the juices redistribute, keeping every slice tender and juicy.
Optional Step for Extra Flavor: Add crushed garlic or fresh herbs like thyme or sage to the butter mixture for even more aroma and taste.