Pour 2 tbsp of melted butter into your baking dish & sprinkle with 2 tbsp of grated Parmesan cheese.
In the bowl with the potatoes add and mix 1/2 cup of sour cream, 4 oz of softened cream cheese, 2 tbsp of softened butter & 1/3 cup of grated Parmesan cheese.
Beat the potatoes until they are smooth. Season with salt & pepper.
Transfer to the prepared dish & dot with butter & Parmesan cheese. Cover & refrigerate for up to 3 days. When ready to bake just bring to room temperature for about 30 minutes & bake at 350 degrees for 30 minutes.