This is a wonderful way to dress-up simple mashed potatoes for a holiday dinner. You can leave out the cheddar cheese for a more traditional mashed potato casserole.
To prevent your potatoes from becoming gummy, make sure you mash them while they're hot, and keep them hot while adding the rest of the ingredients.
8 large russet potatoes, peeled, boiled and mashed
1/2 cup butter, softened
6 ounces cream cheese, softened
1 cup sour cream
4 ounces of sharp cheddar cheese, shredded
1/2 cup grated parmesan cheese
4 green onions, finely chopped
1 T salt
In large bowl, combine mashed potatoes and remaining ingredients. Spoon into a large, round casserole dish, and bake uncovered at 350 degrees for 45 minutes. Serve with homemade turkey gravy.