They are called, microwave bowl potholders and is sold as an e-pattern by Rita's creations on Etsy. She says the pattern is copyrighted.
I don't know if a technique can be copyrighted, I don't think so. It seems to be a square with darts from each corner and a dart from each side, all heading down toward the center and stopping when you reach the size of the bowl bottom. The dart has to be a bit fatter when it starts to turn and then taper down. It is really only a hot pad. I will make one and see how it turns out in a couple hours.