Chocolatier mold. Neat, but I'd probably misplace the mold after the first batch if I tried it. Anyway, if I do need a knob, I'd likely only need just one, so might as well just buy, or make one. I'd most likely make one, in my shop, for my stuff, I don't particularly care if it looks museum quality or not, and I'm sure not going to sell anything with knobs on it. So, all considered, I'll just make any knobs I need.