Put the 10 cups of water in a large pot and set on high to boil.
Peel and cut the potatoes. About 5 of them need to be diced very small, the remaining 7 cut into medium size pieces, small enough to put into your mouth without having to cut them. Set those 7 aside. Add the small, diced potatoes to the boiling water and allow to boil for about 15 minutes.
Add the larger pieces of potato into the pot along the bouillon cubes, and half of the cilantro. Put on a lid and allow to boil for about 15 minutes, or until the larger potatoes are tender.
When the large potatoes are tender, add the 1 1/2 cups of milk and turn it down to medium-low , allowing the soup to simmer for about 4-5 minutes. Remove from heat and let sit about 10 minutes.
Remove the half bunch of cilantro from the soup and discard. Serve the Locro up in bowls and allow family/guests to add in chunks of cheese, sliced avocado, and minced cilantro. I like to wait a few minutes and allow the cheese to melt. Enjoy!