It is not safe to keep frozen food on the counter while waiting for the oven to preheat. Leaving frozen food at room temperature for an extended period can lead to the growth of harmful bacteria, potentially causing foodborne illnesses.
The best practice is to transfer the frozen food directly from the freezer to the preheated oven. This minimizes the time the food spends in the "danger zone," which is the temperature range between 40°F (4°C) and 140°F (60°C) where bacteria can multiply rapidly.
If you need to preheat your oven before cooking, plan ahead and take the frozen food out of the freezer just before the oven is ready. Alternatively, some recipes allow for cooking frozen foods at a slightly lower temperature for a slightly longer time to accommodate the need for preheating the oven.
Always follow the cooking instructions provided on the food packaging or in the recipe to ensure the safe and proper preparation of frozen food. If there are no specific instructions, it's best to thaw the food in the refrigerator before cooking or adjust the cooking time and temperature accordingly to accommodate cooking from frozen.