The helm is an extension to the Architexture Cowl by Jennifer Weissman. It follows that pattern up to Section IV: Ribbing before casting off the chin.
This extension is free but the original pattern is paid and can be bought through the original designer.
The head section is worked back and forth with some face shaping. The top is then split into 3 panels to create the head shaping before sewing it all together.

I used just under 2 skeins of De Rerum Natura Cyrano (in Goeland).
Pattern is worked on 5.5mm needles throughout.