This is a delicious crema like Nutella. I first discovered this on a trip to Sicily at Pasticceria Savia. I ordered a croissant filled with pistachio since it was something I never really saw before. Once I tried it, I was hooked.
The cream has a Nutlella-like consistency but the main flavor comes from pistachios.
Here is a way to make it at home. Or you can buy some from Amazon below.