Use toothpicks so as to check if your brownies need more baking.
The first toothpick (on the left) demonstrates what underdone or underbaked brownies look like. Generally, if you take brownies out at this stage, theywill be extremely wet in the center andwill only be firm if refrigerated. They will be difficult, if not impossible, to cut neatly at roomtemperature.
The center toothpick is from a batch of brownies that are completely baked but notoverdone. There is still a smear of brown color on the toothpick- but NO wet batter-and there are a few moist crumbs sticking to the toothpick after it comesout.These brownies are done!
The final toothpick on the right was inserted in an overbaked pan of brownies. It is completely clean, with no brown color and no moist crumbs. It’s so clean that you can’t really tell that you inserted it in a pan of brownies.
(taken from the recipeforperfection.com website)