1. In a large pot or Dutch oven, cook the chopped bacon over medium heat until crisp. Remove the bacon and set it aside, leaving about 1 tablespoon of bacon fat in the pot.

2. Add the butter and chopped onion to the pot. Cook for 4 to 5 minutes until the onion softens. Stir in the garlic and cook for 30 seconds.

3. Sprinkle the flour over the onion mixture and stir well. Cook for 1 minute to remove the raw flour taste.

4. Slowly pour in the chicken broth, stirring constantly until smooth. Add the milk and heavy cream, then stir to combine.

5. Add the diced potatoes, salt, and black pepper. Bring the soup to a gentle simmer.

6. Reduce the heat to medium-low and cook for 18 to 22 minutes, or until the potatoes are very tender.

7. Lightly mash some of the potatoes in the pot with a potato masher to thicken the soup while still leaving some chunks.

8. Stir in the shredded cheddar cheese a little at a time until melted. Add the sour cream and stir until the soup is creamy and smooth.

9. Taste and adjust seasoning if needed. Ladle into bowls and top with crispy bacon, green onions, and parsley before serving.