Place the cookies in the freezer for at least two hours before assembling the sandwiches. When you are ready to assemble, let the ice cream thaw on the counter for a few minutes. It should be scoop-able, but still firm. Scoop about a 1/3 cup of ice cream onto one cookie and top with another cookie.
Press gently between your hands to spread the ice cream between the cookies. Return the cookies to the freezer for at least a couple hours prior to eating. (Although, if you can resist them that long, you are stronger than I am!) Enjoy!
* I prefer Monster Cookies without the m&ms when they are going to be made into ice cream sandwiches. I usually make half the batch without the m&ms just for this purpose.
Tips for freezer storage: These can be stacked in a large airtight container and they will keep well that way. They can also be wrapped individually in foil. I do not recommend storing them in zipclose or sandwich bags, they will absorb some of the plastic smell and I really didn't like that. For what it's worth, the no one else in my family was bothered by it.