I happened to have some lavender bulky yarn sitting in my yarn stash to use.
I used a 9mm hook and chained 40. Make a loop by slip stiching to the first stitch being careful not to twist it. Chain 2 (counts as double crochet). Then double crochet in each stitch around. Join with slip stitch. Repeat for a total of 9 rounds.
You will end up with a rectangular block. This is super simple to make and works up very quickly.