Matcha cookies can last up to one week if stored properly. The most important factor when storing matcha cookies is to keep them sealed in an airtight container at room temperature or in the refrigerator. If kept in the refrigerator, they will last even longer, up to two weeks, if stored away from moisture and other foods that may cause them to spoil. Additionally, consider keeping matcha cookies in the freezer if you plan on storing them for longer than two weeks. When ready to eat, thaw the cookies at room temperature or warm them slightly in the oven before indulging!