In a bowl, place 2 crushed garlic cloves, rosemary, salt, pepper and extra virgin olive oil. Add the potatoes to the bowl so as to season them.
Make diamond shaped incisions on the potato skins. Season with salt and pepper. Brush the cockerel skin with maple syrup. Insert some rosemary into the cockerels to flavor.
Drizzle some oil on the bottom of the casserole and then alternate layers of onions, seasoned potatoes and cockerel.
Cook in a preheated oven at 180° degrees for 40 minutes.
Once cooked, remove the garlic and rosemary and serve