Like pie dough, galette dough can easily be frozen before baking. If you choose to do this, flatten the dough into a disc about 2" thick prior to freezing. Wrap it tightly in plastic wrap and store it in a freezer-safe zip-top bag. As mentioned above, you'll need to thaw the dough before you can use it. I'd recommend moving it to the refrigerator to thaw overnight, and then letting it sit at room temperature just until its pliable enough to roll. Don't let it get warm though; the butter in the dough needs to stay cold!