Question: what is a 2 dc cluster?
Answer: The 2 Double Crochet Cluster Stitch(2 dc-cl) is my personal favorite. It uses the minimum number of stitches needed to be classified as a cluster stitch, it creates a nice solid fabric, and it is the most flat of the cluster stitches. The 2 dc-cl is most closely related to a dc2tog (think of it as a half sibling).