I made these because I really couldn't find what I was looking for and if I did I knew I could make one just as good!!
Its pretty much a double crochet around til its rather flat the I just double crocheted til I got it to fold in a little. There are three rows of the counterpain stitch I think its called (you go to make a single crochet, YO, pull through one loop, YO pull through last two) and the last one before the brim is dc.
I changed from a size K I think to size H...so the brim would be tighter..
Enjoy! Also on mah blog!