Preheat your oven to 400°F (200°C) while scrubbing the russet potatoes under cold water. Prick each potato with a fork several times.

Bake the prepared potatoes directly on the oven rack for 45-60 minutes or until a fork easily pierces them.

While baking, melt 4 tablespoons of butter in a large pot over medium heat. Stir in 1/3 cup of all-purpose flour and cook for 1-2 minutes.

Gradually whisk in 4 cups of whole milk into the roux, stirring continuously until it thickens.

In a separate pan, cook 4 strips of bacon until crispy, about 5-7 minutes. Transfer to a paper towel to drain.

Peel and chop the baked potatoes into small cubes, then add to the soup pot and stir gently.

Stir in 1 cup of shredded cheddar cheese and 1/2 cup of sour cream, allowing the cheese to melt completely.

Season with salt and pepper to taste, and serve hot, garnished with crispy bacon and green onions.