We knit the Simple Pleasures hat as a gift (a two to three night project, the ribbing is a bit slow going) . . . The ribbing is knit in a double strand of lace weight yarn (we used Malabrigo Lace colour 9 Polar Morn) The top is knit in one strand each Malabrigo Lace and Rowan Kidsilk Haze (we used colour 642 Ghost). The perfect hat--light as a cloud, soft and warm, with just the right amount of slouch . . . . . . a hat that will be hard to part with.   We'll just have to cast on for another!