As promised, here's my felt donut ornament. I went with red frosting again, as on my crochet donut ornament, and I'm generally pleased with how it turned out.
It took me couple of tries to figure out the proportions of the donut, since sewing it changes things up a bit. In the end, for the donut base, I cut a circle that was 5 inches in diameter, with a 1.25-inch diameter hole. For the frosting, I cut a circle that was 5.25 inches in diameter and also with a 1.25-inch diameter hole. Once I made sure the frosting aligned with the sewn donut, I played with the circle, giving it "swirls" to make it more frosting-like. My donut turned out a little big -- it's by far the biggest ornament on the tree, beating out the crochet reindeer, but I'm quite fond of it.