Stir together mashed potatoes and milk in a large glass bowl.
Microwave, uncovered, at HIGH 11 to 13 minutes. Add remaining ingredients, stirring until cheese is melted.
*1 (3-ounce) package cream cheese, softened and cubed; 3 tablespoons butter; and 1 minced garlic clove may be substituted.
Note: For testing purposes only, we used Alouette Garlic & Herbs Spreadable Cheese.