1. Preheat oven to 400° F. Peel potatoes, and cut into 8 equal-sized pieces. Boil in water until fork-tender. Strain the potatoes; place back in pot over low heat. Let potatoes dry while stirring until all steam releases from potatoes and they are dry to the touch.
2. Mash potatoes until well-mashed, dry and crumbly. Add cheese, salt and pepper; stir to combine. Pour in butter, cream and egg yolks. Stir until well-combined. 
3. Using a piping bag with a star tip, pipe the potatoes into a decorative swirl that is 2 inches wide and 1 inch high on parchment paper-lined baking sheet. Beat remaining egg with 2 teaspoons water. Brush potatoes with egg wash. Bake for 20 minutes or until golden-brown.

Calories: 78, Fat: 5 g (3 g Saturated Fat), Cholesterol: 51 mg, Sodium: 96 mg, Carbohydrates: 7 g, Fiber: 1 g, Protein: 2 g.