This sock recipe contains instructions for making a basic toe-up sock, and includes my variation on an afterthought heel with gusset and heel flap.

The construction of the heel fits well even with high insteps, and has the advantage of a
super-comfortable heel cup with absolutely no wrap/turn short-row stitches.

It’s based on a 64-stitch sock, but math is included for a custom length, and for a variety of stitch counts.