I have had decent luck with making one-sided folders and using a No More Shims mat as the top of my sandwich (I bet any soft, siliconish mat for embossing would do). I punched or cut shapes from a cereal box, then glued them to a piece of cereal box. My brick one I used Mod Podge and then covered it with a couple of coats of MP to make it slicker, but I don't think that is necessary. I also did the same with die cut alpha letters to make personalized embossed stuff, names and initials.
I used the brick one on my number 13 advent calendar box
for the fireplace, and the dots for snowflakes thru the window on this one
(I brayered blue on the debossed side).
It helped to spritz the CS with alcohol to get a crisper impression. You can do this with the negative cut out piece as well, if it is not too detailed an image. I just write the Big Shot sandwich on the folder. I love that you can make them any size. I am going to do one with hearts this weekend.