Clean the extra duck fat and criss cross the skin left. Pan fry fat side first without adding any oil, season and seal well from both sides. Using a peeler slice thin carrot wafers and cut the leeks in strips. Remove duck from pan and using the same pan toss together the carrots, leek, thyme, raisins and grapefruit segments until softened. Add grenadine toss again and remove from pan. Keep the same sauté pan and on low heat add the garlic butter and melt to infuse with the flavours left in the pan, than pour in the wine And stock to reduce by half. Slice the potato and sauté in a pan until nearly cooked through than finish underneath the duck breast in the oven.