How can I make a silky smooth, rich mash?
Here is how we made pomme puree at the restaurant I used to work at, for a very well known (in Canada anyway) French chef:

Peel and boil as many potatoes as you need. Cook until slightly underdone.

Run the potatoes through a ricer/food mill. Then--this is key--scrape the result through a tami--a very fine mesh sieve. Most often used for sifting flour. Usually about 14-18" diameter, looks like a drum.

Return resulting potato to a pot, add melted butter, cream, salt, pepper, nutmeg to your desired consistency, stirring all the time.

If not serving immediately, chill as fast as possible, and reheat to order in a pan using a little more cream to loosen it up.

IMPORTANT: you must work as fast as possible; the potatoes need to stay hot the whole time or will become gluey.