What I did:
With lighter colour
chain 3 & form a ring.
Round 1: 10 dc in the ring, join, chain 3
Round 2: 2 dc in each dc, join, chain 3
Round 3: (1 dc, 2 dc) around, join, chain 3
Round 4: (1 dc, 1 dc, 2 dc) around, join, chain 3
Round 5: (1 dc, 1 dc, 1 dc, 2 dc) around, join, chain 3
Round 6: (1 dc, 1 dc, 1 dc, 1 dc, 2 dc) around, join, chain 3
Round 7: (1 dc, 1 dc, 1dc, 1 dc, 1 dc, 2 dc) around, join, finish off, hide ends
With darker colour join yarn, chain 3
Round 8-16: chain 3, 1 dc in each dc, join
Finish off, hide ends
For a longer had continue with more rounds until you have it the length you want.

Ear flaps
Row 1: Join yarn on side, 12 dc, turn
Row 2: chain 3 dc across, do a decrease using the last 2 stitches
Row: 3-end repeat row 2 until you only have 2 stitches

Trim
sc around entire edge of hat… at tips of ear flaps, chain 30 sc back up the chain & continue with the sc around the hat, join. Weave in ends

Ears (make 2)
with darker colour
chain 3 & form a ring
Row 1: 6 dc in the ring, turn
Row 2: chain 3, 2 dc in each dc across, turn
Row 3: chain 3 2 dc, 1 dc across
Fasten off.. use tail end to sew ears on to hat

Eyes (make 2)
with black
chain 3 & form a ring.
Round 1: 6 dc in the ring, join
Round 2: chain 3, 2 dc in each dc, join
Fasten off.. use tail end to sew eyes on to hat

Mouth
with red:
chain 12
Round 1: sc in each chain across, 2 sc on the end rotate the chain & 1 sc on the opposite side
Round 2: 2 sc, sc, hdc, hdc, dc across to 4 before the end, hdc, hdc, sc, 2 sc.. repeat around the other side. (this makes the mouth wider in the center & thinner at the ends.
Round 3: using the lighter colour that you used on the monkey hat
join yarn, chain 3, dc in each dc around with 2 dc at the “corners” so that the mouth lays nicely. Finish off & use the tail end to sew the mouth on the hat

Hair
chain 3 & form a ring.
Round 1: 12 dc in the ring, join, chain 3
Round 2: 2 dc in each dc, Finish off
Join yarn around one of the dc in the first round, chain 25 & slip stitch around the next dc in the first round, (chain 25 & slip stitch around the next dc in the first round) repeat around. the chains will form loopy hair. When yo reach the point where you started, fasten off & hide ends. Sew on to top of hat.

Had it done in less than 2 hours.

The hat took 1 full skein of the Barley colourway & just bits of the other colours.