I used a size D crochet hook and baby yarn for this tutorial.
1. Start with a magic loop. Ch 1.

2. Sc x 5 in loop.

3. Pull loop tight and then join last sc to ch st with sl st. Ch 1. (do not turn)

4. Sc in stitch of joining. *2 sc in next sc, 1 sc in next sc* repeat from * rest of round (9-10 st total). Join with sl st, ch 1. (do not turn)

5. Sc in each sc. Join with sl st. Ch 1. (do not turn)

6. Repeat previous row. Use blunt end of crochet hook to assist in turning hat inside out.

7. Repeat previous row.

8. Cut yarn and weave in ends. Gently turn up edge of hat, using fingers and blunt end of crochet hook to shape hat.

1. Cast on 12 stitches onto double-pointed needle.

2. Distribute stitches evenly (four apiece) onto three double pointed needles.

3. Using needle shown on right, knit first stitch of needle on left (to join circle).

 4. Continue to knit around using fourth needle. [tip: After knitting off one needle, use the same needle to knit the first stitch off the next needle. This keeps your work from having vertical rows of slightly stretched out stitches.] Knit approximately 7 rows.

after about 3 rows

after about 6 rows

5. Cut end of yarn leaving about a 4 inch tail. Carefully slide the stitches from the needle next to the tail end of yarn onto a small crochet hook.

6. Use the crochet hook to pull the tail end of yarn through the stitches.

 7. Repeat this twice more until there are no more stitches on knitting needles.

8. Pull the yarn end tight to cinch in the stitches. Pull the yarn end through the center hole using the crochet hook. Tighten it, weave in the end, then cut.

9. Weave in the beginning tail of yarn, then gently roll up the ‘brim’ of the hat.