Method
Prepare your fire; it doesn’t need to be big or particularly voracious.
Place the duck breasts on a board, skin side up. Use a very sharp knife to score shallow, criss-cross cuts in the duck skin, about 1cm apart, going through the skin and down into the fat. Season the skin with fine salt.
When the fire is glowing gently, set a grill over it. The temperature is right when you can hover your hand above the grill for a maximum of 5 seconds. Place the duck breasts, skin side down, on the grill. Nestle the garlic and rosemary next to them and season the surface of the duck breasts with salt and pepper.
Cook the duck breasts for 25–30 minutes. This relatively long, gentle cooking softens the fat and colours and crisps the skin. If the fat drips and causes the fire to flare up, dampen the flames with a spray of water, or remove the meat from the grill until the flames have settled. You don’t want flames scorching the skin of the duck.
Turn the duck breasts over and cook for a further 10–15 minutes on the flesh side. I cook them medium-rare, aiming for an internal temperature of about 55°C on a digital probe thermometer. If you prefer them more well done, aim for 60°C. Once cooked to your liking, remove the duck breasts from the grill and leave them to rest somewhere warm for 10–15 minutes.
Slice the duck breasts thickly and serve with the soft grilled garlic, a green salad, new potatoes and bread.