1. Freeze cookies in layers separated by a sheet of waxed paper.
2. Freeze cookies unfrosted because the frosting may cause the cookies to stick to one another. Also, cookies tend to absorb moisture from the frosting and lose their crispness.
3. Before baking bar cookies, line the baking pan with foil, leaving 2 inches extra at each end. Add the batter, bake, and cool the bars in the lined pan as directed. Lift the foil to remove the cooled bars. Wrap in foil, seal, and freeze. Frost and cut the bars after thawing.
4. To freeze cookie dough, pack it in freezer containers. (For sliced cookies, roll and wrap the dough as directed in the recipe.) Freeze cookie dough for up to six months. Before baking, thaw frozen dough in the container in the refrigerator. If the dough is too stiff to work with, let the dough stand at room temperature to soften.