Microwave Potatoes: Prick potatoes with a fork and microwave them for 12 to 15 minutes until soft. Allow them to cool, then peel and chop into chunks.
Bacon Preparation: In a medium-high heated skillet, fry the bacon until it reaches a crispy texture. Move it to a paper towel-lined plate to drain. After cooling, break the bacon into small pieces, keeping up to 1 tablespoon of the bacon fat.
Aromatic Base: In a sizable pot, combine melted butter with the retained bacon fat. Cook minced garlic and onion until they're soft and fragrant, about 2 to 3 minutes.
Thicken Soup Base: Stir in flour to the pot for 1 to 2 minutes. Slowly mix in milk and half-and-half until smooth. Gradually incorporate chicken stock, simmering lightly.
Seasoning and Thickness: Add in salt, garlic salt, and black pepper, continuing to simmer until the soup slightly thickens, about 5 to 7 minutes.
Add-ins: Before removing from heat, stir in most of the cheese and bacon, reserving some for garnish, along with the sour cream. Mix in the potato chunks, breaking them to desired sizes.
Serving: Serve the soup hot, garnished with the set-aside cheese, bacon, and freshly chopped chives.