Chop the thick-cut bacon into bite-sized pieces. In a large pot over medium heat, cook the bacon for about 8 minutes or until crispy. Transfer the bacon onto a paper towel-lined plate, leaving the bacon fat in the pot.

In the same pot with the bacon fat, add the chopped yellow onion and sauté for about 5 minutes. Stir in the minced garlic and cook for another minute.

Sprinkle the all-purpose flour over the mixture, stirring constantly for about 2-3 minutes to form a light golden roux.

Gradually whisk in the chicken broth and bring the mixture to a gentle boil. Add the diced russet potatoes and let it simmer uncovered for 15-20 minutes.

Use a potato masher or immersion blender to mash some of the potatoes for a creamy base while leaving some chunks for texture.

Add unsalted butter, heavy cream, sharp cheddar cheese, and sour cream. Stir until melted and smooth, then season with salt, pepper, and optional smoked paprika.

Return crispy bacon to the pot and stir into the soup for about 2-3 minutes, being careful not to boil.

Ladle the soup into bowls and top with chopped green onions, additional cheddar cheese, and crispy bacon.