Switch up the usual mashed potatoes this year and instead serve them au gratin style for Thanksgiving.
Preheat the oven to 350 degrees.
Combine the potatoes, 2 cups of the cream, shallots, cheese, salt, and pepper in a bowl and mix together thoroughly. Rub a casserole dish with the butter. Layer the potato mixture in the casserole dish and pour the rest of liquid in the bowl over top and lightly top with more cheese. Cover with foil and poke 3-4 air holes in foil. Bake for 20 minutes, then remove the foil and cook for another 15 minutes to lightly brown the top.