You will need: 
Double knitting wool – white and oddments of colours.

Instructions:
Main Part of Hat
Cast on 28 sts and knit 2 rows.
Continuing in stocking stitch work 16 rows.
Cut a length of wool and thread through stitches and pull tight.

Scarf: Cast on 40 to 50 stitches in a coloured wood then cast off or you can just do a chain stitch scarf like the picture.

Nose: Cast on 4 sts knit one row and then cast off.

Making Up:
Join seam and sew the scarf in place as per picture.
Fold the nose and sew along edge.
Sew to face and add a mouth.
You could use small buttons for the eyes or beads, wiggly eyes or French knots.