Yes, the vegan oatmeal dough for these cookies can be prepared up to two days in advance and stored in the fridge in an airtight container; these can be baked straight out of the fridge, or the dough can be left to reach room temperature before baking. As there is no vegan butter in this recipe, but mashed banana instead, the dough will slightly change color if not used straight away, however, it will still be good to use.