I was recently asked for a Tutorial on the ruffled hat I made here. I tried to write on the photo as I went, but I don't like how that came out. So I will write under the picture instead. The white hat was made with a white men's t-shirt, which gives you a lot more stretch then the tank I chose for this pink one.
I traced an old hat and added a little to each side and height because it was for 0-6 months. I folded that pattern in half
make sure all ends are even, fold the t-shirt over and place pattern piece on top, on fold. If you do it this way both piece will be cut out at the same time
Starting at bottom use zig zag stitch, slightly stretch the hat part as you sew, so you don't loose the stretch in the hat
Lay right sides together and sew using zig zag stitch, slightly stretching again