Really, it’s up to you! The goal of baking the cookies a second time after slicing them is to dry out the dough and make them crisp. If you’re hoping to dunk your biscotti into coffee, you may want them to be a bit more on the crunchy side. Simply bake them for an extra few minutes. However, if you want a cookie that’s chewy and only a little crisp, bake them for the amount of time indicated in the recipe.