Remove the turkey from the refrigerator about 1 hour before roasting to bring it closer to room temperature.
Preheat the oven to 325°F (165°C).
Pat the turkey completely dry with paper towels, including inside the cavity.
In a small bowl, mix the softened butter, olive oil, salt, black pepper, rosemary, thyme, and sage until well combined.
Gently loosen the skin over the breast and rub half of the herb butter underneath the skin.
Rub the remaining butter mixture all over the outside of the turkey.
Fill the cavity with the onion, lemon halves, and garlic.
Place the turkey breast-side up on a rack set inside a large roasting pan.
Pour the chicken broth into the bottom of the roasting pan.
Roast the turkey uncovered, basting occasionally if desired, until a thermometer inserted into the thickest part of the thigh reaches 165°F (74°C). This typically takes about 13–15 minutes per pound.
If the skin begins to brown too quickly, loosely tent the turkey with foil.
Remove the turkey from the oven and let it rest for at least 20–30 minutes before carving.