Should I line sheet pans with parchment paper or aluminum foil?

Use heavy-duty aluminum foil for easy cleanup with meats and high-fat sausages. Use bare metal or parchment paper for vegetables where you want direct conductive browning. Never use wax paper in an oven (it smokes and melts).

Sheet Pan Dinner Logistics: Thermal Zones, Staggered Timing, and Moisture Evaporation

The Fallacy of the "Dump-and-Bake" Sheet Pan Dinner

Popular cooking videos suggest tossing raw chicken, broccoli, and diced sweet potatoes onto a single sheet pan and baking for 25 minutes.

The thermodynamic reality:

Sweet potatoes are still crunchy and raw in the center (need 35 mins).
Broccoli has turned black and charred (needed 15 mins).
Chicken breasts are dry, stringy, and chalky (needed 14 mins).
Evaporating vegetable water has pooled across the pan, steaming the chicken instead of roasting it.

The Three Rules of Flawless Sheet Pan Engineering

Rule 1: Staggered Chronological Loading:

T - 30 Mins: Load dense vegetables (diced potatoes, carrots, Brussels sprouts) tossed in oil and salt. Roast at 400°F.
T - 15 Mins: Push vegetables to the sides, make space in the center, and add medium proteins (chicken thighs, pork chops, sausage links) and tender vegetables (peppers, onions).
T - 8 Mins: If cooking fast seafood (salmon fillets, shrimp), add during the final 8–10 minutes only.

Rule 2: Pan Metal Physics (Dark vs Light Aluminum):

Dark / Well-Seasoned Half-Sheet Pans: High emissivity ($e \approx 0.9$). Absorb radiant thermal energy and caramelize vegetable contact points.
Bright Shiny Aluminum: High reflectivity ($e \approx 0.1$). Reflects infrared radiation, leading to soft, pale bottoms.

Rule 3: Thermal Edge Zones:

The outer perimeter and corners of a sheet pan experience the highest heat and airflow.
Place cut sides of vegetables facing the perimeter/pan floor to maximize browning.