1. In a large pot, cook the chopped bacon over medium heat until crispy. Remove and set aside, leaving the bacon fat in the pot.
2. Add the butter to the pot and melt it. Stir in the diced onion and garlic, cooking until the onion becomes translucent and fragrant, about 5 minutes.
3. Add the cubed potatoes to the pot, stirring to coat them in the onion and garlic mixture. Season with salt and pepper.
4. Pour in the chicken broth, bringing the mixture to a boil. Reduce the heat and let it simmer until the potatoes are fork-tender, approximately 15-20 minutes.
5. Using an immersion blender, blend the soup until smooth. If you prefer a chunkier texture, blend only half of the soup.
6. Stir in the milk, cheddar cheese, and sour cream, allowing the cheese to melt completely. Adjust seasoning with additional salt and pepper as needed.
7. Return the bacon to the pot, reserving some for garnish. Stir to combine and heat through.
8. Ladle the soup into bowls, garnishing with reserved bacon and a sprinkle of chopped chives.

This step-by-step process is one I cherish, as it allows me to recreate the magic of my childhood kitchen, where patience and love were the secret ingredients to every meal.