Preheat your oven to 400°F (200°C) and adjust the oven rack to the lower middle position.

In a medium bowl, combine the softened unsalted butter with crushed culinary lavender, fresh thyme leaves, kosher salt, minced garlic, honey, and lemon zest to make the herb butter.

Pat the whole roasting chicken dry and loosen the skin from the breast and drumsticks. Spread two-thirds of the herb butter under the skin and rub the remainder on the outside. Season with salt and black pepper.

Stuff the chicken cavity with the quartered lemon and fresh thyme sprigs. Truss the legs with kitchen twine.

Place the chicken breast-side up in a roasting pan and roast for 1 to 1 ¼ hours or until juices run clear and the internal temperature reaches 165°F (74°C).

Baste the chicken with pan juices halfway through roasting for a golden glaze.

After roasting, let the chicken rest for at least 10 minutes before carving and serving.