At first glance you might think this is a Buttonhole Wheel, but it isn't. It is made up of Back Stitch and keeps it shape beautifully, unlike the Butthole Wheel which has a tendency to loosen up a bit.
I found the Eyelet Wheel Stitch at Sarah's hand Embroidery Tutorials.
Work it like this:
First draw a circle, mark the centre and the spokes.