For the racks of lamb, preheat the oven to 200C/400F/Gas 6.
Season the lamb with salt and freshly ground black pepper. Heat an ovenproof pan until hot, add the butter and, when foaming, add the lamb skin-side down and cook for 1-2 minutes.
Turn the lamb over and fry on the other side for 30 seconds. Then place the meat, bone-side down, into a roasting tin. Place in the oven for 12-18 minutes, or until cooked to your liking. Remove the lamb from the oven and leave it to rest in a warm place for five minutes.
For the port reduction, bring all of the port reduction ingredients to the boil in a saucepan, then reduce the heat and simmer the mixture until it has thickened to a light syrup, about 5-8 minutes. Strain the mixture into a clean pan and discard the red onion and garlic.
For the sautéed salsify, add the butter to a hot pan. When melted add the salsify and stir-fry for 3-4 minutes, or until tender and golden-brown.
For the seasonal greens, heat a frying pan until medium-hot. Add the butter, seasonal greens and 50ml/1¾fl oz water. Cook gently until the greens are tender. Season to taste with salt and black pepper.
To serve, place a rack of lamb, some seasonal greens and salsify on serving plates and pour the reduction around the plate and over the lamb.