Ingredients
1 teaspoon butter, or as needed
3 large russet potatoes, scrubbed
¼ cup minced shallots
3 teaspoons kosher salt
½ teaspoon freshly ground white pepper
1 pinch cayenne pepper, or to taste
2 ½ cups grated sharp white Cheddar cheese
1 ¾ cups sour cream
Directions
1
Preheat the oven to 400 degrees F (200 degrees C).
2
Poke holes into potatoes using a knife. Wrap each potato in aluminum foil and place on a baking sheet.
3
Bake in the preheated oven until potatoes are very tender and easily pierced with a knife, about 1 hour and 15 minutes.
4
Let potatoes cool to room temperature. Unwrap and place on a plate. Cover with plastic wrap and refrigerate until completely chilled, 8 hours to overnight.
5
Preheat the oven to 425 degrees F (220 degrees C). Butter a casserole dish.
6
Leave skin on potatoes. Use a cheese grater to shred potatoes into a large bowl. Add shallots to potatoes; season with salt, white pepper, and cayenne. Toss with two forks until well combined.
7
Add Cheddar cheese and mix well. Gently toss in sour cream until barely combined.
8
Transfer mixture to the prepared baking dish, piling it up high, then patting it down very lightly.
9
Bake in the preheated oven until piping hot and the top is browned, 30 to 35 minutes.
Notes
You can use 1 1/2 to 2 teaspoons of fine salt instead of kosher salt. Ground black pepper can be used instead of white.
If you do use shallots, note that a little will go a long way because they are raw. Feel free to sauté them in a little butter to take off the sharp, raw edge.