Prep Oven & Roasting Pan: Preheat oven to 375°F (190°C) with rack in lower-middle position. In a large heavy roasting pan fitted with an elevated rack, arrange the onion wedges, halved garlic heads, and lemon halves. Pour 2 cups of poultry bone broth into the bottom of the pan to keep the oven moist and prevent drippings from scorching.

Mix Herb Butter: In a bowl, combine softened butter, minced garlic, chopped rosemary, thyme, sage, smoked paprika, kosher salt, and cracked black pepper until whipped and fragrant.

Season & Butter Under the Skin: Thoroughly dry the turkey breast inside and out with paper towels. Gently slide your fingers between the skin and meat to separate them, creating pockets. Smear half of the garlic herb butter directly underneath the skin against the meat. Rub the remaining herb butter generously all over the exterior skin.

Roast to Golden Perfection: Set turkey breast skin-side up on the roasting rack. Roast at 375°F for 60 to 75 minutes (tenting loosely with foil after 45 minutes if the skin reaches desired deep golden color) until an instant-read meat thermometer inserted into the thickest part reads 160°F (71°C).

Mandatory Resting: Transfer turkey breast to a carving board. Tent loosely with foil and let rest undisturbed for 15 to 20 minutes. Carryover cooking will bring the internal temperature to a safe, perfectly juicy 165°F (74°C) while the juices redistribute.

Whisk Pan Gravy: Pour pan juices through a fine-mesh strainer into a glass measuring cup and skim excess surface fat. In a saucepan over medium heat, melt 2 tbsp butter, whisk in flour for 1 minute to form a golden roux, then slowly whisk in the strained pan drippings. Simmer for 3 to 4 minutes until thickened into a glossy, velvety gravy.

Carve & Serve: Carve breast meat across the grain into thick, succulent slices. Arrange on a warm holiday serving platter garnished with fresh sage leaves, rosemary, and roasted garlic. Drizzle warm golden pan gravy over the top and serve immediately.