M-I-L birthday

My card today was made a while ago, but I had to keep it hidden as it was for my mother-in-law's birthday in September.  A fellow demonstrator and I got together one day, and she and I each had a try at making one of these cards.   I've just spent 20 minutes on Pinterest trying to find out what the name of this sort of card is called, but I can't find any today.  

So, from the outside this is just like a normal card ...

 But when you open it up ...

.. it has an extra layer with a little window.