Store this delicious peppermint bark in an airtight container at room temperature for up to two weeks. Stack the peppermint bark pieces in layers separated by parchment paper so the bark won't stick together. If the room temperature is above 72 degrees Fahrenheit, I recommend storing the peppermint bark in the refrigerator instead. This sweet treat also lasts well in the freezer for long-term storage. Stack the pieces on a plate with parchment paper between each layer and wrap the dish in aluminum foil or plastic wrap.  Then, place it into a large freezer-safe Ziplock bag.  When ready to dive into this chocolatey goodness, allow the bark to thaw in the fridge overnight.