Everyone has a different level of preferred sweetness in their brownie and also the sweetness of your batch of brownies will vary by the type of dates you use so you may need to make a slight adjustment if you want them to be a little sweeter. After mixing the wet and dry ingredients together, taste for sweetness. If your healthy vegan brownies aren't sweet enough you have two options. First, you can use a sweeter chocolate chip such as milk chocolate chips or a dark chocolate with a lower percentage of cacao for a sweeter final vegan date brownie. The second option is to stir in some additional sugar one tablespoon at a time until you achieve the desired sweet flavor.