Why This Recipe Works

Food baked in foil packets or en papillote has been lauded for both healthfulness and ease of cooking and cleanup, but our first attempts turned out overcooked chicken, mushy vegetables, and overall blandness. We chose quick-cooking boneless chicken breasts, and to ensure that they’re seasoned throughout, we sprinkle them all over with salt before assembling the packets and then refrigerate them for at least an hour before cooking. Leaving headroom at the top of the packet allows maximum steam circulation for even cooking, and checking the temperature of the chicken through the foil lets us monitor its progress. Finally, layering the heartier sweet potatoes under the chicken insulates it from the hot pan. Some assertive seasonings and a few splashes of extra-virgin olive oil and no one would mistake this for diet food.

Before You Begin

To ensure even cooking, buy chicken breasts of the same size. If using table salt, use only 1/8 teaspoon for each entire breast. Refrigerate the pouches for at least 1 hour before cooking.

Instructions

Spray centers of four 20 by 12-inch sheets of heavy-duty aluminum foil with vegetable oil spray. Microwave oil, garlic, ginger, and pepper flakes in small bowl until garlic begins to brown, 1 to 1½ minutes. Combine potato slices, radishes, celery, onion, 1 teaspoon salt, and garlic oil in large bowl.

Pat chicken dry with paper towels. Sprinkle ⅛ teaspoon salt evenly over each side of each chicken breast, then season with pepper. Position 1 piece of prepared foil with long side parallel to counter edge. In center of foil, arrange one-quarter of potato slices in 2 rows perpendicular to counter edge. Lay 1 chicken breast on top of potato slices. Place one-quarter of vegetables around chicken. Repeat with remaining foil, potato slices, chicken, and vegetables. Drizzle any remaining oil mixture from bowl over chicken.

Bring short sides of foil together and crimp to seal tightly. Crimp remaining open ends of packets, leaving as much headroom as possible inside packets. Refrigerate for at least 1 hour or up to 24 hours.

Adjust oven rack to lowest position and heat oven to 475 degrees. Arrange packets on rimmed baking sheet. Bake until chicken registers 160 degrees, 18 to 23 minutes. (To check temperature, poke thermometer through foil and into chicken.) Let chicken rest in packets for 3 minutes.

Transfer chicken packets to individual dinner plates, carefully open (steam will escape), and slide contents onto plates. Drizzle vinegar over chicken and vegetables and sprinkle with cilantro. Serve.