I already have confited duck legs — lucky me! They’re already fully cooked, so no need for the long cook time for them. But the potatoes need it, don’t they? Unless maybe they’re cooked in duck fat but the legs were put on later and the oven temperature reduced?
Also can I use a half duck or chicken legs for this dish?
Nigella's Roast Duck Legs And Potatoes (from FEAST) cooks duck legs on top of chunky cubed potatoes. As the duck cooks it renders its fat and this bastes the roasting potatoes. If you already have confit duck legs then they will not need as much cooking, but they will still need reheating and crisping up. We would suggest heating the roasting tin in the oven for 5 minutes with 3-4 tablespoons of the confiting fat. Once the fat is hot, add the potatoes and carefully turn them in the hot fat, season with salt and pepper and scatter over a little thyme, then roast the potatoes for about 30 minutes, until they are starting to turn golden at the edges. Put the duck legs alongside the potatoes, then cook for a further 45-50 minutes, until the duck has heated through and the skin is crisp and the potatoes are bronzed. If the duck skin is still slightly soft, transfer the duck to a baking sheet, turn the oven up to 200°C/180°C fan/400°F and cook the duck on the baking sheet for about 10 minutes to help crisp up the skin. However, we would mention that as we have not tried the recipe with confit duck, we are unable to guarantee the results.
We have not tried the dish with half a duck, but as the breast has less fat than the legs, there is a risk that the duck breast becomes dry and overcooked, so we would prefer to use duck legs if possible. Chicken legs also have less fat than duck legs and may not render enough fat to crisp the potatoes properly. However, Nigella has several chicken traybake recipes, which would be good for chicken legs. We would suggest considering the Spanish Chicken With Chorizo And Potatoes.