Years ago, I made a hat for my niece. I didn't make a note of the pattern, but I remember what it looked like. It looked a lot like this hat (but, obviously, my memory tells meit was infinitely better). It looked more like a real cable stitch, and I think I know now how I did it - it was a 3x1 rib. I'll try that some other time.
For this hat:
CO96, Work 2x2 rib with 4mm, switch to 4.5mm, place marker at the start of the round (2 Knit stitches)
P1, *K2, P2 to end for 6 rounds
P2, K2 for 6 rounds
K1, *P2, K2 for 6 rounds
Continue like this, staggering the rib by 1 stitch every six rounds.
On the last row, I staggered the stitch to the right instead of the left, so I incorporated it into the pattern... abandoned the pattern - and continued in standard 2x2 rib.
For the crown:
P2tog all purl stitches, for one round, K2, P1 the next round, K2tog all knit stitches the next round, K1, P1 for one round, then K2 together until you have few enough stitches to finish the hat (8-12st).
I made the pom pom with a pom pom maker, which I love. Available here.