By far the warmest hat I have ever had.
This 'shroom hat' is one I knit up last winter and am now starting to offer for sale by commission.
A relatively quick knit, since it is with such fun bulky yarn, it proved more than worthwhile to make. Hubby teases me and calls it my shower cap, but my ears are so snug and warm that I can't hear his mockery. Besides, I've gotten nothing but compliments from everyone else. And, like a shower cap, it has plenty of room to tuck my hair up inside, or fit over a bun.