This recipe is from the famous Chez Panisse Cafe Cookbook by Alice Waters.
1 fresh duck foie gras, about 1 lb.
1/3 cup hazelnuts
1 clove garlic
1 1/2 tsp. sherry vinegar
1 1/2 tbsp. red wine vinegar
6 tbsp. extra-virgin olive oil
6 large handfuls rocket (arugula)
1. Prepare the foie gras several days in advance. Let it soften at room temperature for about an hour. When it is pliable, pull the two lobes apart, grasp the veins, and gently pull to remove them. Don't worry about disfiguring the foie gras; it will be pressed later. When all the veins have been removed, lightly season the two lobes with salt and reshape them into their original form. Cut a 2-foot length of cheesecloth, place the foie gras at one end, and roll up the foie gras in the cloth. After 2 1/2 turns, trim off any remaining cheesecloth and tie the ends firmly, making a tight sausage shape. In an earthenware or glass vessel that is 4'' taller than the rolled foie gras and at least 2'' wider, make a 1 1/2'' layer of salt. Add the foie gras and cover completely with a layer of salt at least 1'' deep. Place a weight on top (a full wine bottle works well), and refrigerate for 3 to 4 days.
2. In a preheated 400° oven, toast the hazelnuts for about 15 minutes or until golden and aromatic. Meanwhile, make the vinaigrette. In a mortar, mash the garlic to a paste with a little salt. Add the sherry vinegar, red wine vinegar, 1/2 tsp. salt, and freshly milled pepper. Whisk in the olive oil, taste for acid and salt, and adjust. While the nuts are still warm, rub them in a clean kitchen towel to remove their skins. Chop the nuts coarsely. Wash and dry the rocket.
3. Retrieve the foie gras from the salt and remove the cheesecloth. Wrap the foie gras in plastic and keep it very cold while preparing the salad, either in a bowl of ice in the refrigerator, or, briefly, in the freezer. Dress the rocket lightly with the vinaigrette, divide among 6 chilled plates, and sprinkle with the hazelnuts. Use a sharp vegetable peeler to make shavings of the cured foie gras over each salad. Be generous. Finish with a flourish of the pepper mill. The foie gras left over will keep a week in the refrigerator, well wrapped.