01 - Set the oven to 275°F to prepare for slow roasting.
02 - Pat the turkey breast dry thoroughly with paper towels to ensure crisp skin.
03 - Combine olive oil, minced garlic, thyme, rosemary, paprika, kosher salt, black pepper, and lemon zest in a small bowl.
04 - Generously rub the seasoning mixture all over the turkey breast, working it under the skin where accessible.
05 - Place onion quarters and lemon halves in the base of the roasting pan and set the turkey breast skin side up atop them.
06 - Pour broth carefully into the bottom of the pan to enhance moisture during cooking (optional).
07 - Roast uncovered for 2 hours or until the thickest part reaches an internal temperature of 160°F.
08 - Optionally, increase oven heat to 425°F for the last 10 minutes to achieve a crisped skin.
09 - Remove turkey from oven, loosely tent with foil, and rest for 15 minutes before slicing and serving.