I saw this technique over on the CASE Study blog and loved what I saw there.
It also struck me a s a fabulous way to use up some of the mountains of DP I have sitting in drawers in my craft room.
The file for this dear little bird is from Silhouette Online and the paper from a Paper Cellar stack I've had for yonks. The paper is simply placed behind the aperture which has been cut out.
The sentiment is from Penny Black.
Here is the same file used on a slightly differently proportioned card base, with a sentiment die cut from Simon Says Stamp die. I think this stack is from Basic Grey. .. it's so long since I used it. I'm not sure, but there are some fabulous papers in this one.