To check if vegan brownies are done baking, insert a toothpick in the center of the batch. If it comes out with a few moist crumbs sticking to it, the brownies are done. If the toothpick comes out completely clean, it means they have been overbaked and may turn out dry. Remember that brownies continue to bake as they cool, so it's best to underbake slightly and check them 5 minutes before the expected baking time is over.