Thoroughly wash your veggies before chopping; then add to your steamer basket (all together). You will want everything to cook through until fork tender, especially the beets, so keep this in mind when cutting so things will cook evening. Steamers cook differently so check occasionally. It was about 18 minutes in our steamer.
While the veggie mixture is steaming, heat a pan for your haddock to just under medium. Add olive oil, fish and cook for about 3 minutes on each side. Add in fresh thyme when flipping to the second side. *Please note cooking times will vary depending on the thickness of each cut of fish; please watch closely to prevent burning or under cooking. Haddock should flake when done.
When the veggies are done, transfer to a deep mixing bowl and use a stick blender, food processor or blender. Mix, pulse and/or puree until you reach the consistency of your liking. Add to serving dishes, top with haddock and sprinkle with fresh thyme and cold chopped mango.