Yes, you absolutely can freeze them. I actually have some in my freezer right now. I placed a sheet of parchment paper in between two layers of blondies and placed them in a freezer-safe resealable gallon bag before freezing. Just be sure to get as much of the air out as possible before sealing the bag. When you are ready to serve them, take the bag of frozen blondies from your freezer and set it on the counter to let them defrost. It doesn't take long for them to thaw.