Allow the apple crisp to cool, then cover it with a paper towel and wrap the whole thing in plastic wrap.
You can leave the apple crisp at room temperature for two days, or you can refrigerate it for up to five days. For longer-term storage, you can freeze the apple crisp.
Make sure the apple crisp is room temperature all the way through before adding any sort of covering. If you cover the crisp prematurely, it won’t stay crispy for long.