Paleo Sweet Potato and Watercress Soup

Mine did not look like this.  It looked like purple porridge.  This one's much prettier. 

Just a quick post so I can share the recipe for the yummy soup I made last night.  Warning:  It comes out looking like purple porridge, but is soooo good.  I got the original recipe here.  Excellent recipe.  The directions are easy to follow.  To make it Paleo, all I did was leave out the white potato.  I bought two Okinawan sweet potatoes because that sounded super yummy to me, hence the color of the soup.  The Watercress was from my friend's aquaponic farm system, so I had a whole bunch of it.  The watercress had a strong, peppery flavor before adding it to the soup, so I didn't add very much.  I could have added much more, it ended up losing a lot of flavor in the few minutes it was in there.  Also, I added a store bought broth to it, per the suggestion of one of the commenters.  Because my vegetarian friend was joining us for this meal I used 4 cups of Organic Vegetable broth, it did have some canola oil, but, whatever.  I added two cups of water to make the six cups of liquid.  I also sprinkled on a dash of Cayenne Powder, which I think added a nice touch.  I was thinking that if I make myself another round today or tomorrow, I will probably use a chicken broth and add some of the meat I have.  The meat turned out a little tough when I made it the other day, so adding it to a slow cooking soup might be a better use.  I also was thinking that if I had remembered to bring my coconut milk to the party, I would have added a spoonful of the thicker, creamier stuff from the top of the can to the top of a bowl of soup before serving it.