Peel the potatoes and cut them into medium pieces. Place them in a pot and cover with water. Boil the potatoes, cooking them until they are soft. Then, drain the liquid out and place the potatoes into a mixing bowl.
Using a masher, give them a rough mash. Then, add the goat cheese, butter, sour cream, and salt. Mash thoroughly, making sure to fully incorporate all the ingredients throughout.
Add the milk and then mash again until the potatoes have a smooth and creamy texture.
Spoon the mashed potatoes into an oven-safe casserole dish and then sprinkle the Parmesan cheese on top. Bake at 350ºF for 40 minutes. Once a golden-brown crust has formed, remove it from the oven and serve.
