To start, I used a paper pattern to cut out two pieces each of the pink flannel and the black velvet. After some experimentation with a couple different types of wire and threading systems, I realized I had some styrene plastic in the back of the closet, so I cut another piece in that shape.
I sewed the fabric together, right sides together, turned them right-side out and then stuffed them with the stiff plastic.
The pieces still looked a little sloppy, so I pressed them with an iron. Because the plastic is thin, it became a little malleable when heated so I was able to shape the ears into a lovely curved shape.
And here's the finished product!