Fry bacon in a skillet until crisp, remove, chop, and place in a medium soup pot.
Add butter to bacon drippings in skilllet, and heat until melted. Added chopped potatoes and leeks (or onions), salt and pepper lightly, and saute until slightly browned.
Add potato/leek mixture to bacon in soup pot, add bouillon cubes and water. Bring to a boil, reduce heat and simmer for about 20 minutes, or until potatoes are soft.
With a potato masher, break up potato cubes into smaller pieces, leaving a few larger chunks.
Add evaporated milk and cream (if using), stir and bring to a boil.
Remove from heat, cover, and let rest for 5 to 10 minutes.
Add salt and pepper to taste.