Adopted from this pattern, this is the adult sized version.

Crochet Pattern: Blanket Stitch Beanie.
Round 1: ch 2, 10 dc in magic circle. sl st in 2nd chain: 10 dc
Round 2: ch 2, turn, 2 dc in each dc around, sl st in 2nd chain: 20 dc
Round 3: ch 2, turn, (2 dc in next dc, dc in next dc) around, sl st in 2nd chain: 30 dc
Round 4: ch 2, turn, (2 dc in next dc, dc in next 2 dc) around, sl st in 2nd chain: 40 dc
Round 5: ch 2, turn, (2 dc in next dc, dc in next 3 dc) around, sl st in 2nd chain: 50 d
Round 6: ch 2, turn, (2 dc in next dc, dc in next 4 dc) around, sl st in 2nd chain: 50 dc
Round 7: ch 2, turn, (2 dc in next dc, dc in next 5 dc) around, sl st in 2nd chain: 60 dc
Round 8 – 18: ch 2, turn, *(2 dc, sc) in next st, skip 2 sts, repeat from * around, sl st in first dc: 22 shells. Finish off at row 18