Microwave potatoes as directed on package. (Do not mash.)
Meanwhile, beat egg whites in medium bowl with mixer on high speed until stiff peaks form. Spray 2-qt. casserole with cooking spray; sprinkle 1 Tbsp. Parmesan evenly onto bottom and up side of casserole.
Place potatoes in large bowl; beat with mixer until smooth. Stir in shredded cheese, sour cream, milk, egg yolks, remaining Parmesan and half the onions. Gently stir in egg whites; spoon into prepared casserole.
Bake 40 to 45 min. or center is set and top is golden brown. Sprinkle with remaining onions.
Cut 4 oz. (1/2 of 8-oz. pkg.) PHILADELPHIA Neufchatel Cheese into cubes; use instead of the sour cream.
Calories From Fat
% Daily Value*
Total Fat 10g
Saturated Fat 6g
Trans Fat 0g
Total Carbohydrates 17g
Dietary Fiber 2g
* Percent Daily Values are based on a 2,000 calorie diet.
8 servings, 1/2 cup each
* Nutrition information is estimated based on the ingredients and cooking instructions as described in each recipe and is intended to be used for informational purposes only. Please note that nutrition details may vary based on methods of preparation, origin and freshness of ingredients used.