Yes, you can keep macarons in an airtight container in the refrigerator for several days or even up to a few weeks without them losing their freshness. They can also be frozen and thawed to enjoy. You can also make macaron shells and cover them with plastic wrap in the refrigerator or freezer until you are ready to add your filling. This is one of the reasons macarons have become so popular–they are a great treat to transfer home from a trip overseas.