3 pounds russet potatoes
3 ounces grated Gruyere cheese (try your microplane if you have one)
¼ cup Kerrygold butter, melted (or in my case, mostly melted)
½ cup milk
¾ cup whipping cream
3 tablespoons Kraft grated Parmesan cheese (I used shredded)
Preheat the oven to 400 degrees. Scrub the potatoes and poke several holes in each with a fork. Bake until a fork pierced into one of the thicker ones meets little resistance, approximately 45 to 60 minutes. Cool potatoes briefly. Then, cut them in half. Using a towel in your hand to keep the potatoes from burning you, spoon the flesh from the peels and into a large bowl. Discard the peels.
Mash the potatoes a few times with a masher and add the melted butter. Continue to mash the potatoes until they are evenly coated with butter. Add the milk and continue to mash until the potatoes are the consistency that you like. You can add a splash more milk if you need to get to a good consistency. Add salt and pepper to taste. (Seriously, taste it…you need good mashed potatoes as a base for this amazing topping).
Spread the potatoes into a greased 3 quart baking dish. Depending on how much the potatoes have cooled during this process, you might cover them and put them in a warm oven (perhaps 250 degrees while you prepare the cream. The potatoes only go into the oven for an additional 10 minutes so they need to be warm before you add the topping).
Whip the cream until it is fluffy, but soft and fold in Gruyere cheese. Spread over the potatoes and sprinkle Parmesan cheese on top. Bake at 500 degrees for 10 minutes
Source : allrecipes.com