Season the duck fillets and cook them in their skin with some peanut oil. In order to prepare the lemon julienne, start by peeling the lemons. Mince the peeled skin and boil it in water. Drain the peeled skin and cook again in the water, adding some sugar and salt. Cook the endives in a pan with some butter and sugar to caramelize. Season with pepper. Lightly saute the Belgian Endives in butter in a shallow pan, over a hot fire. Turn the Belgian Endives after one and half minutes to saute both sides. To prepare the sauce, start by removing the grease left by the duck fillets. In the same pan, add some water and duck gravy. Add the Arabica coffee beans, a spoon of lemon juice, and some butter. Cover the pan and let simmer for about 25 minutes Drain the sauce after cooking. For the ending, place the endives on a serving dish. Remove the skin from the duck fillets and cut in sufficiently thick slices, before placing them on the same dish. Add the lemon julienne and the Arabica coffee sauce.