Preheat oven to 200 degrees Celcius / 400 degrees Fahrenheit / Gas mark 6.
Lay duck breasts skin down on a baking tray and freeze for 30 minutes. Once the fat has firmed up, carefully scored the skin.
Peel and cut sweet potatoes into small evenly sized pieces. Coat with olive oil, salt and pepper and roast until soft and browning. Mash the sweet potatoes and add honey. Enrich with two to three tablespoons of rendered duck fat when reheating.
Peel carrots and place on a baking sheet. Coat with olive oil and one tablespoon of Verjuice. Roast until the carrots are soft and start to darken
Trim the bottom of the Bok Choy and split lengthwise down the middle. Wash thoroughly.
Wash coriander. Remove stalks and reserve for later use.
Place pan on a medium heat. Season skin of duck breast. Sear the skin side of the breast first. Once golden, seal the rest of the meat. Pour of the rendered fat into a container. Return pan to the heat and pour in a ⅓ cup of the grapefruit lemonade. Lightly steam the duck breast for a few seconds. Place the breasts into a baking tray and pour a little of the cooking liquor into the tray. Cook for eight to ten minutes. Rest for at least five minutes and then slice.
Return the pan to a high heat and pour in the rest of the grapefruit lemonade. Reduce by two thirds. Add in one tablespoon of Verjuice and the remained of the cooking liquor. Any juices left in the tray used to cook the breasts may also be added along with three or four coriander stalks.
Thicken sauce with the cornflour slurry.
In a clean pan gently heat two teaspoon of duck fat and garlic. Increase the heat and add the sauté the Bok Choy until tender.
Add carrots and heat through.