In a small bowl, combine the minced garlic, chopped rosemary, chopped thyme, olive oil, salt, pepper, lemon zest, and juice to create a herb paste.
Pat the turkey breast dry with paper towels. Carefully separate the skin from the meat (without removing it completely) by sliding your fingers underneath, creating a pocket.
Divide the herb paste into two portions. Spread one portion directly under the skin, rubbing it evenly across the breast meat.
Rub the remaining herb paste over the skin of the turkey breast.
Place the quartered onion in the bottom of a roasting pan, creating a bed for the turkey.
Place the turkey breast on top of the onion and pour the chicken broth around it in the pan (not over the turkey).
Roast in the preheated oven for about 1.5 to 2 hours, or until the internal temperature reaches 165°F (75°C). Baste the turkey with the pan juices every 30 minutes for added flavor and moisture.
Once finished, remove the turkey from the oven and let it rest for 15-20 minutes before slicing. This allows the juices to redistribute within the meat.
Notes
Slice the turkey breast and arrange it on a large platter garnished with fresh herbs and lemon wedges for an inviting presentation. Serve alongside your favorite sides to complete the meal.