Place the chopped bacon in a large pot or Dutch oven over medium heat. Cook until crispy, stirring occasionally, about 8-10 minutes. Use a slotted spoon to transfer the bacon to a paper towel-lined plate, leaving about 2 tablespoons of bacon grease in the pot. Set the cooked bacon aside.

Add the unsalted butter to the bacon grease in the pot. Once melted, add the diced onion and celery. Sauté until softened, about 5-6 minutes.

Add the minced garlic and cook for another minute until fragrant, stirring constantly to prevent it from burning.

Sprinkle the all-purpose flour over the cooked vegetables. Stir constantly for 1-2 minutes to cook out the raw flour taste. This will create a roux that thickens the soup.

Gradually pour in the chicken broth while whisking continuously to prevent lumps from forming. Bring the mixture to a simmer.

Add the cubed potatoes, salt, and black pepper to the pot. Stir to combine. Increase the heat to bring the soup to a boil, then reduce the heat to low, cover the pot, and let it simmer for 15-20 minutes, or until the potatoes are fork-tender.

Remove the pot from the heat. Use an immersion blender to blend the soup directly in the pot until it reaches your desired consistency. For a completely smooth soup, blend thoroughly. For a heartier texture, pulse a few times, leaving some small potato chunks.

Return the pot to low heat. Slowly stir in the heavy cream and half of the reserved crumbled bacon. Heat gently until the soup is warmed through, but do not allow it to boil as this can cause the cream to curdle.

Taste the soup and adjust the seasoning with additional salt and pepper if needed.

Ladle the hot soup into bowls. Garnish generously with shredded cheddar cheese, a dollop of sour cream, fresh chives, and the remaining crumbled bacon before serving.