1 Cook the lentils in a pot of boiling water until al dente, 15-20 minutes. Drain in a sieve, rinse with cold water and drain well.
2 Peel carrot and parsley root and cut into 5 mm (approximately 1/4-inch) pieces.
3 Cut leek into 1 cm (approximately 1/2-inch) pieces, then rinse well and drain.
4 Rinse sage leaves and pat dry. Rinse quail and pat dry, then season inside and out with salt. Tuck sage leaves into the neck cavity.
5 Tie quail legs with kitchen twine, then pin together the neck openings with toothpicks.
6 Heat the oil in a roasting pan over high heat (place over two burners). Cook the quail until golden brown on all sides, then remove from pan. Add the prepared vegetables and cook over medium heat, stirring frequently, until glazed and turning tender.
7 Add the tomato paste and cook, stirring, until fragrant, then pour in the chicken stock and stir. Return quail to the pan and bake in a preheated oven at 175°C (fan: 150°C, gas mark 2)(approximately 350°F/convection 300°F), on the second rack from the bottom, until cooked through, about 15 minutes.
8 Wash apples, quarter, remove core and seeds and chop finely.
9 Add lentils, diced apple, honey, balsamic vinegar and red wine vinegar to the roasting pan and continue cooking until lentils and apple are tender and sauce has thickened, 20-25 minutes more, seasoning lentils with salt and pepper at the end of cooking. Serve hot.