What's that cake

[Grinner]

called that you find in City coffee shops? It's got a crumbly biscuit base, a layer of caramel and then a thin layer of chocolate. Is it some sort of fridgecake, and how's it made?

That choccy one with bits of biscuit in it and dusted with flour too.

[Berni]

[Grinner]

Haven't had a piece in 15 years as it isn't known in California so fancied making some.