Pull the turkey breast from the refrigerator 45 minutes before roasting so it takes the chill off. Preheat your oven to 375 degrees. Place the onion quarters, lemon halves, and thyme sprigs in the bottom of a roasting pan and set a rack over them.

In a small bowl, mix together the softened butter, lemon zest, garlic, parsley, sage, salt, and pepper until fully combined and smooth.

Pat the turkey breast completely dry with paper towels, skin and all. Using your fingers, gently loosen the skin from the breast meat by sliding your hand underneath, working carefully so you do not tear the skin. Press roughly two-thirds of the herb butter directly onto the meat under the skin, spreading it as evenly as you can across both sides of the breast.

Rub the remaining herb butter over the outside of the skin. Drizzle the olive oil over the skin and rub it in, then season the outside lightly with the extra salt. Place the turkey breast skin-side up on the rack in the pan.

Roast at 375 degrees for 1 hour and 30 minutes to 2 hours, depending on the size of the breast. Start checking the internal temperature at the 1-hour 20-minute mark. Insert a meat thermometer into the thickest part of the breast without touching bone. You are looking for 165 degrees.

If the skin turns deep brown before the inside is done, tent a sheet of foil loosely over the top. Remove the foil for the last 20 minutes of cooking to let the skin re-crisp.

Once the turkey reaches 165 degrees, pull it from the oven and let it rest uncovered on the rack for 15 minutes before carving. This rest time lets the juices redistribute so every slice stays moist. Carve into clean slices along each side of the breast bone and serve.