Since it is just the hat section, I think I would do the fabric sheet method. You could use a thin interfacing with the reverse pattern drawn on, lay it over the right side of the velvet and stitch the outline of the simple shape with a small stitch length. Trim the edges, cut a slit in the back of the dryer sheet or interfacing and turn right side out. The shape will now be ready to appliqué with all the raw edges enclosed and stay stitched so the velvet doesn't fray.
You might want to slightly round the sharp angles or pointed edges on the pattern piece so it is easier to turn.