En papillote refers to the technique of cooking food in parchment paper or foil.
Here's a healthful cooking technique borrowed from the French: cooking en papillote. En papillote refers to the technique of cooking food in parchment paper or foil. Foods such as fish and vegetables cook in their own flavorful juices without added fat. Cooking en papillote can be used for a variety of foods. To adapt the technique to your taste, experiment with combinations of fish (or meat or poultry), quick-cooking vegetables (such as sliced zucchini, grape tomatoes, thinly sliced carrots, sliced mushrooms, and sliced green onions), herbs, and a little broth or wine.