1. Preheat oven to 140 degrees.
2. Combine all the ingredients, except the fat. Rub into the legs and let it sit in the fridge for 4-5 hours.
3. Wash duck legs well, place into baking tray and cover with duck fat. Cook for 2-3 hours until duck is tender and remove from the fat. The fat can be kept in the firdge and used at any time.
4. Heat and pan and sear the skin until crispy. Alternatively, you can crisp up the skin under a grill in the oven.
5. Cook the lentils gently until just soft. Strain and dress in olive oil and sherry vinegar while warm.
6. Cut the brussel sprouts in half and roast in a moderate oven with chunks of kaiserfleisch until very well cooked. When cooked, toss lentils in a pan to warm through and add sprouts and kaiserfelish.
7. Taste and season with sherry vinegar, salt and pepper. Serve with a generous pile of lentils underneath each leg.

Recipe courtesy of Chef Ian Curley