What makes a chocolate temptation cake crunchy?

There's a bakery near me that makes this Chocolate Temptation cake, and after a little searching, I found it online to show you - https://www.cafecremerie.com/items/chocolate-temptation It's this exact cake and it's the most delicious cake I've ever had in my life and I've spent way too much money on this one cake in that one bakery (zero regrets). There's a layer of chocolate cake in the bottom, chocolate hazelnut ganache, cake again, then some sort of a white cream filling, and then the whole cake is drowned in a shiny chocolate glaze. But the best part - something crunchy inside that makes me go "mmmm" in every single damning bite. I need someone to help me divine what in the world is that crunchy bit, so I can have a prayer of replicating at least a semblance of it at home. Please and thank you! submitted by /u/leyameera