chewy cookies

I like a chewy bread and chewy cookies. I have been trying to make chewy cookies based on Alton Brown's Chewy cookie recipe but if I alter the ingredients just a bit, more sugar, more butter, etc I always seem to loose the chewy part.  He uses bread flour which adds more gluten and basically he melts the butter instead of the the usual creaming method.  He claims that bread flour will absorb more liquid from the melted butter making more gluten.