Peel and chop the onion. Heat 1 tablespoon of oil in a saucepan. Fry the onion in it until golden brown. Deglaze with Noilly Prat. Add the lentils and pour in the stock. Bring to the boil, cover and cook the lentils for 25-30 minutes until soft.
Put red wine, vinegar and maple syrup in a pot and let it boil for 5 minutes. Peel the pears, add them to the stock and cook the pears in it for about 6-8 minutes until soft, turning the pears from time to time.
Clean, wash and cut the leek into rings. Heat the remaining oil. Sauté the leek in it. Mix leek and cranberries into the lentils and season with salt and pepper.
Remove the pears from the stock and keep them warm. Let the stock boil down over a high heat for 5 minutes and season the lentil stew to taste sweet and sour. Arrange the pears together with the lentil stew. Serve sprinkled with parsley.