How to achieve a crackle as in Rice Krispies

I am thinking about making protein bars. I confess that I have
eaten some divine Atkins bars, with hazelnuts and dark chocolate,
but I don't like consuming soy protein isolate. (I got those as
part of my storm supplies.) The chocolate and hazelnut are
obviously not a problem, but how can I get a satisfying crackle in
there? No, I don't think I want to use pork rinds in them...
although as I say that I am thinking I could try to do one small
bar (or splot) that way.

Thanks,

Jean B.