Absolutely! I recommend giving the potatoes their first bake and mixing the filling, then making the streusel. Keep the sweet potatoes in an airtight container in the refrigerator and store the streusel in an airtight container in the freezer until you are ready to bake. You can make the streusel a month in advance and the potatoes 2 - 3 days in advance. When ready to bake, assemble and continue with the recipe as normal.