This card uses two similar techniques, masking and reverse-masking. Masking is a simple technique that allows you to use only part of a stamp for your image. It's handy for layering images in front of one another. In this case, I masked the interior of the coffee cup. I did this by stamping the coffee cup on a scrap piece of paper, cutting the center out, and using that center cut-out to "mask" the center of the stamped image on my pink cardstock. So, when I stamped it, it only showed the outline of the coffee cup. Then, I did reverse masking. I used the other part of the scrap paper that I cut (which had the outline of the cup on it), and used that as a reverse mask. It basically covered the outline of the coffee cup on the pink cardstock, so I could fill in the center with something else. I filled the center with Creamy Caramel sponged ink, and then with coffee beans in Basic Brown. It's a fun technique that I'm sure I'll be using many times over again in the future.
There's an excellent tutorial by Beate at Splitcoaststampers. It shows pictures of how to do this fun technique!
Reverse Masking Tutorial at SCS