This is a 2 piece D20 cookie cutter. It is in 2 pieces because that was the easiest method I found for making the cookies without having to fight to get the cookie out.
There are multiple ways you can use the two, but I prefer to:
1) Roll out a large amount of dough
2) Flour the dough and the cookie cutter
3) Press the Imprint into the dough
4) Remove the Imprint and then use the cutter to cut out cookie
5) Move the cookie to a tray using a spatula
Here's hoping all your rolls are 20s this Critmas! (Unless you're the DM).