"En Papillote" refers to cooking in paper -- baking parchment, to be exact. It is a classic French technique with an infinite number of modern variations especially suited to low-fat cooking. Little or no fat is used; instead, ingredients such as herbs, onions, tomatoes, and other aromatics infuse their flavors and aromas into the food as it steams. If it is sealed correctly, the parchment will swell in the oven, creating a billowing packet that can be brought to the table for each diner to break into and enjoy.
1. Fold a 24-inch piece of parchment paper in half crosswise. Starting from the folded edge, cut a half-heart shape so that when opened, the parchment will be heart shaped. Arrange ingredients 2 to 3 inches from the crease.
2. Fold the other half of parchment over the ingredients. Make small overlapping folds to seal the edges, starting at the top of the heart.
3. About 2 inches from the end, twist the parchment twice, gently but firmly, to seal. The paper puffs considerably while cooking, so the seams must be tightly sealed. Packets should not be prepared ahead of time -- liquid in the food may weaken the paper.