Marco Pierre White Mashed Potato

I absolutely adore Marco Pierre White, I think he is amazing, and the King of Culinary Arts.
Both Gordon Ramsay and Mario Batali were of his line cook/staff in the 80's or early 90's.
If, I had the money, I would gladly pay MPW to cook a 7 course meal in a heartbeat!
Anyhow, I saw this technique in one of his videos; but like he said: "in cooking there is no recipe, if there is then it's baking".
This is what I have made for my in-laws dinner.

Ingredients:

6 yukon gold potatoes (important)
1 cup milk
4 tbsp. unsalted butter
salt
white ground pepper
1/2 cup sour cream (optional)

* Preheat your oven to 350F.
* Using a dinner fork, poke each potato 4 times.
* Place it in the oven and bake for 1 to 1 1/2 hrs.
* Cut each potato in half and push trough a potato smasher or vegetable mill. (shown above)
* In medium sauce pan, warm the milk: do not boil. Add the butter and a teaspoon of salt.
* Mix the milk mixture with the mashed potatoes using a whisk until it's creamy.
Sprinkle with pepper.
* Serve with Coq Au Vin. For plating, place the mashed potatoes in the plate first and make a hole in the center, scoop the Coq Au Vin into the hole and garnish with chopped chives.
Enjoy!