Fry the bacon in the soup pot. Remove it from the pot, reserving the grease.
Add the chopped onion to the bacon grease in the pot (or substitute 2 Tablespoons butter or oil in place of bacon grease). Sauté the onion over medium heat until translucent.
Once the onion is translucent, add the minced garlic, chopped potatoes, salt, pepper & broth. Bring to a boil, reduce the heat and simmer 10-15 minutes or until potatoes are fork-tender.
Using a potato masher, mash the potatoes as much or as little as desired. Alternately, use an immersion blender OR remove 3-4 cups of the soup to a blender and blend before returning it to the pot.
Add the milk and heat through, then stir in the cheese.
Ladle into bowls and garnish with bacon, cheese, and green onions.