Preheat oven to 350* and lightly grease or spray a 9x13 baking pan. Set pan aside.
Boil potatoes in a large pot until soft; drain and put into a large mixing bowl
Add in sour cream, milk, butter blending until smooth. Salt and pepper to taste.
Fold in 2 cups of cheddar cheese, bacon, and onion until evenly blended.
Spoon into prepared baking pan and top with the remaining cheese.
Bake at 350* for about 30 minutes or until heated through and cheese is melted. ENJOY!
NOTE: can make this dish the day before, cover with foil/plastic wrap, and refrigerate until next day. Add additional 15 minutes to baking time, if still chilled.
