Preheat the oven to 150°C and combine jus ingredients with 250ml water in a lidded saucepan.
Cook the jus for two hours and then strain through a sieve.
Tie the bird's legs with string and season with salt and pepper.
Brown the bird in 150g of butter in a large casserole while basting.
Roast the bird on a trivet at 150°C for 35 minutes until juices run clear.
Sauté the onion in 50g of butter, add cloves, bay leaves, and milk, then simmer.
Process the bread crusts into crumbs and set the white bread aside.
Bake the crumbs on a tray with butter dots for 10 minutes.
Dice the white bread, stir into the infused milk without the herbs, and add butter.
Rest the bird for 20 minutes and deglaze the roasting tin with the jus.
Fry the kale and cavolo nero in oil until tender and season.
Beat the bread sauce and serve with the bird, greens, jus, and crumbs.