Hello Marta, I completely understand your concern about getting the timing right for your meal prep!
For a standard home oven, the exact preheat time depends on whether you are using basic cookware or a dedicated heat-retaining surface:
1. Standard baking sheet or tray: Preheat your oven at its maximum temperature setting (typically 450°F to 500°F or 230°C to 260°C) for 20 minutes. Although your oven's indicator light may turn off after 10 to 12 minutes, giving it a full 20 minutes ensures the internal walls and air temperature are completely stabilized.
2. Pizza stone or baking steel: Preheat for 45 to 60 minutes at maximum temperature. Materials like ceramic, cordierite, or steel have high thermal mass, which means they require additional time to fully absorb and hold the heat necessary to crisp the bottom crust immediately upon contact.
If you are looking for the most efficient meal prep routine without a pizza stone, set your oven to 500°F, wait 20 minutes, and bake on the center rack for best results. I hope this helps you plan your cooking time accurately!