14 Tbsp unsalted butter, softened and more for the pan
6 pounds Yukon Gold potatoes, peeled and cut into chunks
2 Tbsp plus 1 tsp kosher salt
1 1/2 cup sour cream
1 tsp black pepper
6 Tbsp finely chopped chives
2/3 cup bread crumbs
2/3 cup grated Parmigiano-Regianno cheese
Lightly greased a 9-inch by 13-inch baking pan.
In a large pot, bring the potatoes, 4 quarts water and 2 Tbsp salt to a boil. Boil potatoes until fork tender, about 20 minutes. Drain.
Mash potatoes with 10 Tbsp butter, sour cream, 1 tsp salt and pepper. Mash in the chives. Taste and adjust seasonings, if necessary. Spread potatoes into the prepared pan. Cover and refrigerate for up to three days.
In a small bowl, combine the remaining 4 tbsp butter, bread crumbs and cheese. Mix together until it forms coarse crumbs. Crumbs can be refrigerated for three days.
Heat the oven to 400 degrees.
Sprinkle crumbs over the top of the potato casserole and bake until golden and crisp, 30 to 40 minutes.
Yield: 12 to 14 servings.
