The preheating time for an oven before baking brownies typically depends on the type of oven you are using and its size. In general, preheating an oven for baking brownies is recommended to ensure even and consistent baking results. As a guideline, you should preheat your oven for about 10 to 15 minutes before placing the brownie batter inside.
However, for more accurate preheating times, it's best to follow the specific instructions provided in your brownie recipe. Different brownie recipes may have slight variations in baking temperature and time, so it's essential to refer to the recipe you are using to get the most precise preheating time.
Keep in mind that oven temperature accuracy can also vary from one oven to another. Using an oven thermometer can help ensure that the oven has reached the correct temperature before putting in the brownie batter, as oven temperature dials or digital displays may not always be perfectly calibrated. This will help you achieve the best baking results for your delicious brownies.