Prep & Dry the Chicken: Preheat oven to 425°F (220°C). Remove chicken giblets and thoroughly pat the outside skin and inside cavity completely dry with paper towels. Season the inside cavity generously with 1/2 teaspoon kosher salt and black pepper.

Make Garlic Herb Compound Butter: In a small bowl, mash together softened European butter, minced garlic, finely chopped rosemary, thyme, parsley, sea salt, and smoked paprika until a smooth, fragrant paste forms.

Apply Herb Butter Under & Over Skin: Gently slide your fingers between the breast skin and meat to create a pocket without tearing the skin. Spread about two-thirds of the compound butter directly under the skin across both breasts and thighs. Rub the remaining herb butter evenly across the outside skin.

Stuff Cavity & Truss Legs: Stuff the chicken cavity with lemon halves, halved garlic head, and fresh rosemary and thyme sprigs. Tie the legs together firmly with butcher kitchen twine and tuck wing tips behind the shoulders.

Roast to Golden Perfection: Place yellow onion wedges on the bottom of a heavy roasting pan or 12-inch cast-iron skillet, and set the chicken breast-side up on top. Drizzle skin with 1 tablespoon olive oil. Roast at 425°F (220°C) for 70 to 75 minutes, basting once at the 45-minute mark with pan drippings, until skin is deeply golden blistered and internal temperature in the thickest part of the thigh registers 165°F (74°C).

Rest, Carve & Serve: Transfer roasted chicken to a carving board and let rest loosely tented with foil for 15 minutes before slicing. Spoon rich pan drippings over carved meat and serve immediately!