I had copy this pattern from Love Stich blog....
 
HAT PATTERN:
Yarn: Cotton yarn (Sugar 'n Cream also works well with this pattern).
Hook size: F - 3.75mm

Magic circle.

• Round 1: Ch 1, 7 sc through the loop. Do not join, place marker and work a continual round.
• Round 2: 2 sc in each sc around (14 sc)
• Round 3: *1 sc in the next stitch, 2 sc in the next stitch. Continue around from *. (21 sc)
• Round 4: *1 sc in each of the next 2 stitches, 2 sc in the next stitch. Continue around from *. (28 sc)
• Round 5: *1 sc in each of the next 3 stitches, 2 sc in the next stitch. Continue around from *. (35 sc)
• Round 6: *1 sc in each of the next 4 stitches, 2 sc in the next stitch. Continue around from *. (42 sc)
• Round 7: *1 sc in each of the next 5 stitches, 2 sc in the next stitch. Continue around from *. (49 sc)
• Round 8: *1 sc in each of the next 6 stitches, 2 sc in the next stitch. Continue around from *. (56 sc)
• Round 9: *1 sc in each of the next 7 stitches, 2 sc in the next stitch. Continue around from *. (63 sc)
• Round 10: *1 sc in each of the next 8 stitches, 2 sc in the next stitch. Continue around from *. (70 sc)
• Round 11: *1 sc in each of the next 9 stitches, 2 sc in the next stitch. Continue around from *. (77 sc)
• Round 12: sc in each sc around. (77 sc)
• Round 13: *1 sc in each of the next 10 stitches, 2 sc in the next stitch. Continue around from *. (84 sc)
• Round 14: sc in each sc around. (84 sc). Slip stitch to the next 2 stitches. 

You can adjust this flat top to fit your head by adding more or subtracting the last row (84 sts).

• Round 1: Ch 3, 2 dc in the same stitch, skip 2 stitches, *3 dc in the next stitch, skip 2 stitches. Repeat from * till the last shell, join with the beginning chain. (28 shells - 84 sts)
• Round 2: Ch 3, 2 dc in the same space, *3 dc in the next space. Repeat from * to the last space, join with the beginning chain. (28 shells - 84 sts)
• From round 3: Repeat round 2 until you get the desired length.

• Round 1: Ch 1, sc in the same stitch, sc in the next 5 stitches, 2 sc in the next stitch. *sc in the 6 next stitches, 2 sc in the next stitch. Continue around from *. Do not join. (96 sc)
• Round 2: sc in each sc around. (96 sc)
• Round 3: *sc in the 7 next stitches, 2 sc in the next stitch. Continue around from *. (108 sc)
• Round 4: sc in each sc around. (108 sc)
• Round 5: *sc in the 8 next stitches, 2 sc in the next stitch. Continue around from *. (120 sc)
• Round 6: sc in each sc around. (120 sc)
• Round 7: sc in each sc around. (120 sc) 
• Round 8: *sc in the 9 next stitches, 2 sc in the next stitch. Continue around from *. (132 sc)
• Round 9: sc in each sc around. (132 sc)  
• Round 10: sc in each sc around. (132 sc)  
• Round 11: sc in each sc around. (132 sc)