6 1/2 ounces butter (13 tablespoons)
6 cups crumbled cornbread
6 cups torn crusty white bread, such as a baguette
2 cups chopped onion
2 cups chopped celery
1/2 to 1 teaspoon dried sage (optional)
2 teaspoons salt
6 eggs, beaten
1 1/2 cups heavy cream
2 cups turkey or chicken broth
Heat oven to 400 degrees, and butter a 9-by-13-inch baking dish. Melt remaining butter. In a large bowl, combine cornbread, white bread, onion, celery, sage, salt and pepper to taste. Toss until well mixed. Add melted butter, eggs, cream and 1 1/2 cups broth. Mix lightly but well; mixture should be very moist.
Turn mixture into prepared dish. If mixture seems dry around edges, drizzle on remaining broth. Bake 45 minutes to 1 hour, until firm and browned on top.
2 1/2 pounds russet potatoes, scrubbed and cut into 1/4-inch cubes
1 (8-ounce) package cream cheese, at room temperature
1/2 cup unsalted butter, melted, plus more butter for the pan
1 cup sour cream
1/4 to 1/2 cup whole milk
Kosher salt and ground black pepper, to taste
2 1/2 cups freshly grated sharp Cheddar cheese (about 8 ounces)
Chopped fresh parsley, for garnish (optional)
Heat oven to 325 degrees. Put potatoes in a large heavy-bottomed pot and cover with cold water. Set on stove over high heat and bring to a boil, then reduce heat and allow potatoes to simmer until they have just started to soften, about 10 minutes. Drain and set aside.
Combine cream cheese, melted butter and sour cream in a large bowl and stir to combine. Add enough milk so that the mixture is creamy but not soupy. Season mixture with salt and pepper to taste. Add potatoes to bowl and stir gently to combine.
Generously grease a 9-by-13-inch baking dish. Tip half the potatoes into the dish and spread to the edges, then scatter half the grated cheese over the top. Add remaining potatoes and spread to the edges, then top with remaining cheese.