Preheat your oven to 430°F (220°C) on conventional roast setting.
In a small bowl, combine melted butter, olive oil, lemon juice, lemon zest, salt, pepper, parsley, oregano, minced garlic, and rosemary. Stir until smooth and aromatic.
Place the chicken in a large roasting dish and pat it completely dry with paper towels. This helps get that ultra-crispy skin.
Brush half of the citrus herb butter all over the chicken under the skin too, if you can.
Slice off the top of the garlic head to expose the cloves and stuff it inside the cavity along with half a lemon. Tie the legs together with kitchen twine.
(Optional) Arrange carrots and baby potatoes around the chicken, brushing them with some of the remaining butter mixture.
Roast for 1 hour 20 minutes, basting halfway through, or until juices run clear and the internal temperature reads 165°F at the thickest part of the breast.
Baste again once roasted, then broil for 3–5 minutes to achieve that perfect golden finish.
Remove from oven, cover loosely with foil, and rest for 10 minutes before slicing.
Garnish with fresh herbs, spoon over pan juices, and serve warm.