01 - Pierce potatoes with a fork and bake at 400°F for 50-60 minutes until tender. Allow to cool slightly, then peel and roughly chop.
02 - In a large heavy-bottomed pot over medium heat, cook chopped bacon until crisp. Remove with a slotted spoon and set aside on paper towels.
03 - Drain off excess bacon fat, leaving 2 tablespoons in the pot. Add butter, then stir in onion and sauté until translucent, about 5 minutes. Mix in garlic and cook for 1 minute.
04 - Pour in chicken broth. Add chopped baked potatoes to the pot. Simmer over medium heat for 10 minutes, stirring occasionally.
05 - Using a potato masher or immersion blender, mash the potatoes in the pot until desired consistency is reached.
06 - Reduce heat to low. Stir in whole milk, sour cream, and 1 cup grated cheddar cheese until smooth and heated through. Season with salt and black pepper.
07 - Ladle soup into serving bowls. Garnish with reserved bacon, additional shredded cheese, scallions, fresh chives, and a dollop of sour cream.