Combine all ingredients in a large bowl; mix well using an electric mixer. Place in a large, buttered casserole dish.
If serving right away, cover and bake in a preheated oven at 325°F. for 50 minutes.
*How to cook the potatoes: Bring a pot of salted water to a boil. Add peeled potatoes, and cook until tender but still firm, about 15 minutes; drain. Mash, and continue with the instructions for this recipe.
*It's ok to lighten this recipe up a little by using low fat cream cheese and light sour cream.
*You can make this recipe several days ahead and store in the fridge. If baking cold, let stand at room temperature for 30 minutes first.
*If you're lacking oven space, start warming this in a well-buttered crockpot earlier in the day.