Preheat the grill.
Peel the sweet potatoes and cut into 2cm cubes. Place in a saucepan of cold salted water and bring to the boil. Cook for 15 minutes until the potatoes are soft.
Peel and thinly slice the shallots.
Remove the fat from around the duck thighs. Set aside to use when cooking. Remove the skin from the thighs, remove the bone and then shred the flesh by hand.
Heat a frying pan and add a tablespoon of duck fat. Add the thigh meat and allow to caramelise. Add the shallots and cook for 2 minutes. Add the red wine and cocoa powder to the pan and mix well. Cook over a low heat until all the liquid has evaporated (approximately 15 minutes).
Drain the sweet potatoes, return to the pan and then crush with a whisk. Add the butter and the milk to the pan to loosen the mash. Mix until you have a smooth puree. Season with salt and pepper.
Create a layer of sweet potato in the base of each stainless steel serving ring and press down. Add a layer of duck meat, press down again and then add a second layer of sweet potato. Finish with a thin layer of breadcrumbs.
Place under the grill and cook until the breadcrumbs are golden brown.
Carefully remove the serving ring and serve the parmentier with a mixed salad.
«Try making this recipe using pumpkin, butternut squash or potato instead of sweet potato.»