Cook 6 strips of bacon in a large Dutch oven or heavy-bottomed soup pot over medium-high heat until crispy. Transfer to paper towel, crumble, and set aside. Leave about 1 tablespoon of bacon grease in the pot.

Add 1 cup chopped yellow onion to the pot and cook 2 to 3 minutes until softened. Stir in 2 minced garlic cloves and cook 30 seconds.

Sprinkle in ¼ cup all-purpose flour and stir for 30 seconds. Slowly pour in 3 cups milk and 1 cup heavy cream, stirring constantly until slightly thickened.

Stir in 1½ lbs chopped russet potatoes, 2 cups chicken broth, 1 tsp salt, and ½ tsp black pepper. Bring to a boil, then reduce to a simmer and cook 15 to 20 minutes, until potatoes are fork tender.

Carefully blend about half the soup until smooth using a blender or immersion blender. Return the blended soup to the pot and stir to combine. This creates a thick and creamy texture while keeping hearty potato chunks.

Stir in 1 cup shredded cheddar cheese, ¾ cup sour cream, and half of the crumbled bacon. Simmer 2 to 3 minutes until smooth and creamy.

Ladle into bowls and top with remaining bacon, extra cheese, sour cream, and chives.