Duck Magret with Madeira Wine

prepare the sauce first:
peel and wash the onion and chop it very finely. In a frying pan, heat 3 tablespoons of oil and cook the onion for about 8 minutes, until lightly browned. Add the salt and the flour and stir it a few times, stirring all the time, gradually incorporating the broth and the Madeira wine. leave it over medium heat for 10 minutes. pass for a Chinese. reserve the sauce to heat.
peel and wash the potatoes and cut them into slices. Cut the apples into slices, removing the seeds, and spread them with lemon so that they do not darken.
heat a frying pan without anything and, when it is hot, put the breast on the side of the skin (previously some deep incisions will have been made). season the other side and let it cook gently, so that the fat melts without burning, about 10 minutes, depending on the thickness of the breast. turn and leave for 3 to 5 more minutes.
while the magrets are being made, sauté the potato slices in oil and a tablespoon of butter. season them.
put aside a large spoonful of butter and sauté the apples and, when they are almost done, add the sugar.
cut the breast into slices and serve in a pre-heated dish surrounded by the apples and potatoes. cover with part of the sauce and the rest put in a sauce boat.