Cook the turkey bacon: In a large pot over medium heat, cook the chopped turkey bacon until crisp and browned at the edges, about 6-8 minutes. Remove with a slotted spoon and set aside, leaving the rendered fat in the pot.

Sauté onion and garlic: Add the diced onion to the pot and cook until soft and translucent, about 5 minutes. Stir in the minced garlic and cook for 30 seconds more, until fragrant.

Add potatoes and broth: Add the cubed russet potatoes and chicken broth to the pot. Bring to a gentle simmer over medium heat.

Simmer until tender: Let the potatoes simmer gently, uncovered, until a fork slides in easily, about 15 minutes. Avoid a hard boil so the potato edges stay intact.

Mash for texture: Using a potato masher, mash about half the potatoes directly in the pot, leaving the rest in chunks. This creates a thick base with some bite remaining.

Lower the heat: Reduce the heat to low so the soup is barely simmering before adding any dairy, to prevent curdling.

Stir in cream and cheese: Pour in the heavy cream and shredded cheddar cheese, stirring until the cheese melts fully and the soup turns smooth and thick.

Add sour cream: Stir in the sour cream off the heat until fully incorporated, giving the soup a tangy, silky finish.

Season to taste: Add the salt and black pepper, tasting and adjusting as needed. The soup should coat the back of a spoon thickly.

Garnish and serve: Ladle the soup into bowls and top with the reserved turkey bacon, extra shredded cheddar, and chopped chives.