Saute chopped garlic and leeks in olive oil while you peel and dice the potatoes. When the leeks are softened, add the broth and bring back to a boil. Add the potatoes and cook until soft. Add a cup or two of water if needed. While the potatoes are cooking remove the large stems of the cilantro and chop. Add cilantro for the last 5 minutes of cooking. I use a hand blender at this point to smooth the soup, but if you are more patient than me, you can cook it another few minutes until the starch in the potatoes thickens it up.
The broccoli adds more nutritional value but sort of mutes the cilantro. Leave it out for a stronger cilantro taste.
If you're not dairy conscious, serve with a dollop of sour cream on top!