Preheat the oven to 200'C.
Cut or break the Roquefort into small piece. Chop the walnuts and mix together.
Take a chicken breast and gently lift the skin from the meat. Add a spoonful of the cheese mixture and press the skin back down, spreading out the cheese.
Heat a frying pan and add a drizzle of sunflower oil. Add the chicken to the pan, skin side down and cook until golden brown. Turn over and cook for 1 minute on the other side. Transfer to a baking tray and cook in the oven for 10 minutes. Remove from the oven, season with Maldon Sea Salt and pepper and keep warm.
Peel and finely dice the garlic and shallots. Cut the leeks into small dice. Pick and roughly chop the parsley leaves.
Heat a saucepan and add a knob of butter. Fry the shallots and garlic until golden brown, add the leeks and cook for a further minute. De-glaze the pan with the Madeira and reduce it by half. Add the double cream and bring to the boil. Check the seasoning and finish with chopped parsley.
«Check that the chicken is cooked by inserting a knife into the centre - the tip of the knife should be hot.»