Pat the duck dry, inside and out, with paper towels. Trim any extra skin around the cavity. Running your hands beneath the skin, carefully separate it from the flesh without tearing or removing it. Season the outer part of the skin and the cavity generously with salt and pepper, then refrigerate uncovered for at least 6 hours or overnight.
In a small saucepan, add honey, 1 teaspoon lavender and sea salt; slowly heat just to activate the oils in the lavender. Set aside to glaze the duck.
Prepare a small fire on an outdoor grill or fire pit. In a small pot, warm the lard or other fat and add the bourbon, thyme, garlic and remaining lavender.
Split the bird by removing the backbone and cracking the breastplate. Skewer the bird horizontally so it can be flat and placed about 4 inches above the embers. Brush the duck with the lavender-lard mixture and roast until the skin is just starting to color and some of the fat has rendered, about 25 minutes.
Baste the duck with more lavender-lard mixture. Continue cooking until the juices from the leg joints run mostly clear when poked with a paring knife, about an additional 25 minutes. Remove the duck briefly and brush with the infused honey. Continue to roast, rotating the duck as needed, until the skin is caramelized and darkened, about 5 minutes.
Brush once more with the honey, and let rest before carving and serving. Makes 4 to 6 servings. THC amount depends on the amount in the infused honey.