I have had success converting bar cookies, brownies, what have you, with a combination of almond flour and coconut flour.

The general ratio I use is three parts almond flour to one part coconut flour; so for this recipe I'd probably just go with two cups almond and a half cup coconut. I make sure to mix the flours together well (in my sifter!) before adding to the wet ingredients so there aren't clumps of one or the other.

I find almond flour by itself is missing a little gravitas? sturdiness? something that the coconut flour adds back in with its density.

Good luck and happy noshing,

Tabs