1. Season the duck pieces with salt. Heat the oil in a large flameproof casserole (Dutch oven) over high heat, add the duck pieces and sear for 5 minutes until coloured on all sides.
2. Reduce the heat, add the soy sauce and deglaze the casserole by scraping the cooking juices o the bottom of the casserole witha wooden spoon or fish slice (spatula) and incorporate into the soy sauce. Simmer for 5 minutes to reduce the liquid.
3. Add the green peppercorns and cream and simmer for about 25 minutes over low heat.
4. Add the thyme sprigs to the casserole, stir to mix, then serve.