Step 1: Cook the Bacon

1. Cut bacon into small pieces and fry in a soup pot over medium heat until crispy (approximately 10 minutes).
2. Remove bacon and set aside on a paper towel-lined plate. Leave 2 tablespoons of the bacon fat in the pot.

Step 2: Sauté the Onion

1. Add the chopped onion to the bacon fat and cook over medium heat for 5 minutes, stirring occasionally, until soft and translucent.

Step 3: Create the Roux

1. Stir in the flour and cook for 1 minute to eliminate the raw flour taste.
2. Gradually whisk in the milk, stirring to dissolve the flour completely and avoid lumps.

Step 4: Simmer the Potatoes

1. Add the diced potatoes, chicken broth, and minced garlic to the pot.
2. Bring the mixture to a gentle boil, then reduce the heat to low and cover partially. Simmer for 20 minutes or until the potatoes are tender.

Step 5: Mash for Texture

1. Use a potato masher to mash some of the potatoes directly in the pot. This step will thicken the soup while leaving satisfying chunks.

Step 6: Add Final Ingredients

1. Stir in sour cream, grated cheddar cheese, and most of the bacon (reserve some for garnish).
2. Season with salt and pepper to taste.

Step 7: Garnish and Serve

1. Ladle the soup into bowls and top with scallions, reserved bacon, and extra cheddar cheese. Serve warm and enjoy!