Ingredients
- 3 lb. russet potatoes, peeled and cut into 1 inch pieces
- 1 T plus 2 t kosher salt, divided
- 6 large egg yolks, at room temperature
- 1 cup heavy cream, at room temperature
- 1/4 cup unsalted butter, melted
- 8 oz. white Cheddar cheese, shredded (about 2 cups)
- 2 oz. Parmesan cheese, grated (about 1/2 cup)
- 1/2 t ground white pepper
Preparation
Step 1
Place potatoes and 1 T salt in a large pot of water. Bring to a boil over high heat and cook until potatoes can be easily pierced with a knife, about 15 minutes.
Remove and drain well. Return to pot and mash until very smooth. Stir in egg yolks, 1 at a time. Stir in cream, butter, both cheeses, white pepper and remaining 2 t salt until smooth.
Transfer mixture to a lightly greased 13x9 inch baking dish, and let cool at room temperature, about 1 hour. While potatoes are still soft, smooth top with an offset spatula or create a decorative pattern with a spoon. Cover with foil and chill until ready to bake, up to 1 day ahead.
Preheat oven to 350 degrees. Remove casserole from refrigerator while oven preheats. Bake, covered, until heated through, about 45 minutes. Uncover and bake 15 minutes. Increase oven temperature to broil on HIGH, and broil until topping is browned, about 3-4 minutes.