Heat a large skillet over medium-high heat. Add bacon and cook until brown and crispy, about 6-8 minutes. Transfer to a paper towel-lined plate; set aside.
Melt butter in a large stockpot or Dutch oven over medium heat. Whisk in flour until lightly browned, about 1 minute. Gradually whisk in milk, and cook, whisking constantly until slightly thickened about 1-2 minutes. Stir in potatoes and green onions.
Bring to a boil; reduce heat and simmer until potatoes are tender about 15-20 minutes. Stir in cheese, sour cream, salt, and pepper, to taste. If the soup is too thick, add more milk as needed until the desired consistency is reached.
Serve immediately, garnished with green onion, cheese, and bacon, if desired.
Dip your favorite Mason Dixie Biscuit in and enjoy!