This is a delightful design.
Simple, trendy and warm.
And a pom!

I think the yarn the designer used was actually a jumbo even tho it was listed as super bulky.

Held this yarn double. Worked 7 rows plus one row sl st for a hem finish.

Really liked that the design was worked from a MR at the crown and then worked down. I worked the first row of the MR as sc. I worked the design stitch as written thereafter.

Want to make matching fingerless mitts as well.

I have the magazine for Hi-Fi Hat but can’t find it.
Snowdrift Hat is very similar also.

The Vickie Howell Hi-fi Hat uses Cascade Magnum, #6.
option: can use two str worsted together.

Maybe it uses:
Blanket Stitch
Blanket Stitch Hat

Fashion Moment:
Big Yarn Beanie from Anthro website, hand knitted by Mischa Lampert:
Rendered out of touchable wool and topped with a faux fur pom, this hand-knit beanie is a must-have essential as the temperature chills.
After hand-spinning merino wool sourced from New Zealand, designer Mischa Lampert knits each piece in her New York City studio using specially carved needles designed by her father.
$225 retail, $160 sale
Hand-knit Merino wool, Synthetic fur pom embellishment