Preheat the oven to 400 degrees F.
Heat the butter and EVOO in a large skillet over medium heat. Add the thyme, celery, apples, onions, and salt and pepper to taste and cook until tender, 7 to 8 minutes. Transfer the mixture to a bowl and let cool.
Pulse the stuffing cubes in a food processor until crumbs form, then transfer to a bowl and moisten with the chicken stock to soften.
Cover the cranberries with hot water in a bowl and let soften, then drain.
Put the turkey in a large bowl and sprinkle with salt and pepper. Add the stuffing crumbs, apple mixture, cranberries, cheese, poultry seasoning and egg and mix gently to combine.
On a parchment-lined baking sheet, form the turkey mixture into a loaf that is 10 inches long and 4 inches high. Drizzle with EVOO and bake until golden and cooked through, 50 to 60 minutes.
Slice the meatloaf and serve with Cider Gravy and cranberry sauce.
Heat the butter in a saucepan over medium heat. Add the flour and cook, whisking, for 2 minutes. Whisk in the stock, cider and Worcestershire sauce. Season with salt and lots of pepper. Simmer until the gravy is thick enough to coat the back of a spoon. Lightly beat the egg yolk, if using, in a medium bowl. Slowly pour in some of the gravy, whisking constantly to temper the yolk. Whisk in the remaining gravy. Transfer to a gravy boat or serving dish and garnish with parsley, if desired.
Steamed green beans and mashed sweet potatoes are great alongside this meatloaf. For the sweet potatoes, boil 1 peeled and cubed potato per person until tender, then mash with chicken stock, salt, pepper, nutmeg and maple syrup to taste. The meatloaf can be covered and refrigerated for a make-ahead meal. Reheat in a moderate oven or slice and heat in a pan with chicken stock. The gravy, without the egg yolk, can be made ahead of time and refrigerated. Reheat over medium heat and add the egg yolk as directed.