Prepare a mixture of salt, extra virgin olive oil, rosemary, and optional spices like black pepper, garlic powder, or paprika.
Rub this mixture thoroughly all over the capon, ensuring it is evenly coated on both sides.

Wrap the capon tightly in plastic wrap and refrigerate for at least 4 hours, ideally overnight for deeper flavor.

To caremelize the clementines, melt the butter in a skillet over medium heat. Add the sliced clementines and sauté until golden.
Add the sugar and juice of one orange, letting the clementines caramelize gently.
Stir in the vanilla extract and honey, continuing to cook until the liquid reduces slightly. Deglaze with rum, allowing the alcohol to evaporate. Set this flavor-rich glaze aside.

Slice the onion into wedges and place it in a roasting pan with a few whole, unpeeled clementine segments (washed thoroughly).
Place the capon in the pan and transfer to a preheated oven at 220°C.
Roast for 2 hours.

If the capon browns too quickly on top, loosely cover it with aluminum foil to prevent burning.

MIdway through cooking (after 1 hour), deglaze with white wine and return to the oven.
Baste the capon regularly with the pan juices to keep it moist and flavorful.

Once fully cooked, remove the capon from the oven and let it rest briefly.
Carve and serve hot, garnished with the caramelized clementines and pan juices for maximum flavor.