Distinguishing this as a Barrow's Goldeneye, rather than a Common Goldeneye are the head & bill shape. Note short, triangular bill, and steep forehead forming a distinct angle at the bill. Bill coloration is orange (not yellow), and there's orange over much of the bill, with a black tip.

Barrow's Goldeneye females in the winter can have almost entirely orange bills

Common Goldeneye females have yellow for about 1/4 of the bill length at the tip, have more sloping & longer bills, and have a more shallow angle between the bill & the forehead.

Thank you to all the birders who helped me with this. I've identified many female Goldeneyes before, but this one took more study for me than usual. That's fine, as birds are always neat to watch.