Aluminum sheets can simply be folded over the ingredients and sealed with a series of narrow folds. Parchment is also easy to use by following simple steps; we found this method creates the tightest seal for parchment packets:
• Cut 1 (15- x 24-inch) piece of parchment.
• Fold parchment in half crosswise, making a crease down the center.
• Draw half of a heart shape on paper. Cut out heart, and open the parchment.
Layer ingredients in one half of the sheet, making sure to leave at least a 1-inch border around the edges. Top with the fish or poultry, and drizzle with remaining liquids or sprinkle with grated lemon rind or fresh herbs. Use hardy vegetables like cabbage and carrots as a bed on the bottom; add more tender ingredients like tomatoes to bathe the fish or meat with moisture.
• Starting at the round portion of the heart, fold paper, tightly sealing edges with narrow folds.
• Twist the tip portion of the heart to seal.
Bake. Carefully place packets onto an ungreased baking sheet, and bake. Do not cut open the packets to check if food is done. In some instances, we call for a standing time of about five minutes before opening the packet to ensure flavors meld while the poultry or fish finishes cooking in the steam without the risk of overcooking.
Carefully transfer packets to individual plates, and serve immediately. Diners can slice open parchment packets or carefully unfold the foil ones. Use caution because steam will be released when the packets are opened.