Preheat oven to 425 degrees F.

Wrap potatoes in aluminum foil. Bake potatoes on a pan in the oven until done, about an hour. Remove foil and let cool to room temperature. Put potatoes on a plate, cover with plastic wrap, and refrigerate overnight.

Grate the chilled potatoes, including skins. You can use a large box grater or a food processor. (I like the food processor!) Transfer grated potatoes to a bowl and sprinkle in the shallots, 1 3/4 cup cheese, salt, and pepper.

Use your hands to gently toss together. (I guess you could stir it too but you would miss all the fun. Go ahead, plunge those hands down in there!) Then fold in sour cream.

Transfer mixture to a 1 1/2 quart gratin dish, making sure that you don’t compress (or squash, or moosh, or squish) it! Sprinkle the remaining cheese on top.

Bake at 350 degrees F until the top is golden brown, about 30 minutes. Serves 6.