Preheat the oven to 230°C.
Roast the duck carcass in a tin for 15 minutes until browned.
Fry shallots, garlic, herbs, and pepper in butter until well-browned.
Stir in tomato purée and cook for two minutes.
Add red wine and reduce until nearly evaporated.
Add roasted carcass, stock, and 200ml water to the pan.
Simmer for 45 minutes until the sauce is thickened.
Sieve the sauce into a clean jug and skim off fat.
Simmer lentils with stock, garlic, and thyme for 20 minutes.
Drain lentils and keep warm under foil.
Season duck breasts with salt and pepper.
Fry duck breasts skin-side down in sunflower oil until crisp.
Turn duck and cook for 2 to 4 minutes until slightly pink.
Rest the duck under foil for 10 minutes.
Heat vegetable oil to 190°C for deep frying.
Fry parsnip slices until golden and drain on paper.
Toss salad leaves with vinegar, olive oil, lentils, and sliced duck.
Divide salad among four plates and drizzle with sauce.
Garnish with fried parsnips and serve immediately.