Bring potato and water to cover to a boil in a large saucepan; reduce heat, and cook for 15 to 20 minutes or until tender. Drain and return to saucepan. Cook over medium heat for 30 seconds. Remove from heat.
Add cheese and remaining 4 ingredients; beat at medium speed with an electric mixer until smooth. Spoon into a 2 1/2 qt baking dish.