I can't work out how to start it though. The top/crown of a hat in double-knitting. A double-knit i-cord for a couple of rows then carry on from there? I can feel some experimentation coming on.
Any thoughts/ideas anyone? I can find a top-down earflap hat pattern (one free from Interweave recently) and numerous earflap and beanie hat patterns (in the same free pattern compilation, on Ravelry and else-web).
ETA (edited to add): I have an idea of how to start! Start the two 'layers' of hat separately knitting in the round to make two concave/convex circles and then, once they are both large enough (maybe 30 stitches each or so, starting with 3 or 6 stitches each and increasing 3 or 6 times every other round) I combine them to form the double-knitting, knitting the rest of the hat in the round (until the ear-flaps if I add them).