Have you ever seen a sweet potato with chocolate? Well, more like a sweet potato brownie? Nah, honestly, we didn't invent anything here, but it can be surprising ;-)
So, to sum up, the sweet potato flesh provides a soft and tender texture and a lil' sweet taste (but not a vegetable taste, don't worry ;-) ).
And otherwise, it's a regular brownie, so you can add pecans or whatever you want, really!