Preheat the oven to 375 degrees. Spray a 9x12-inch lasagna pan with cooking spray or grease with butter.
Spread the stuffing into an even layer in the prepared pan. Combine the turkey, green beans, and gravy in a bowl. Pour over the stuffing. Combine the mashed potatoes with the cheese and spread over the top of the casserole. Make hashmarks with a fork in the potatoes. Bake for 30-40 minutes or until everything is hot and the potatoes are starting to brown. Sprinkle with paprika and serve.