I’ve made a few donut beads in my day. I have molds and use up scrap clay to fill the form. But I really like this air-filled technique as posted by Page McNall of Palo Alto, California. A little patience and a light touch seem to be the main ingredients needed to create the nice pillowy curves using this technique.
Page actually shows several approaches to making these on her Flickr page. Here is her technique summary, though:
Leave the large air-filled bead inside the metal cutter and select the location you want to cut the small circle. Slowly depress the cutter until you have sliced through all the layers of clay and remove the small cutter. Clean up the edges using an X-acto knife and a rounded smooth tool like a large knitting needle to smooth any rough edges. Carefully remove the air-filled bead and doctor up and outside edges. Now you are ready to bake your masterpiece. Again, thanks to Cate van Alphen for your ideas to improve on this technique.