The silky part comes from two aspects of the recipe:
- Technique: pressing cooked potato through a strainer
- Ingredients: using an oppressive amount of butter, cream and milk.
Here's a shot of the strainer I used. For comparison, I put it next to a very common 3" diameter fine-mesh strainer, the kind you can find in many kitchens.
There's a huge difference between this strainer technique and tools like a potato ricer or press. They will truly mash your potatoes. Using the strainer, the potatoes are in separate strands, and if folded carefully into the butter, cream and milk, they will retain that separation. That unique texture is the magic.
As to the oppressive amount of butter and cream? Well, I'm not going to publish all of Gordon's amounts, but if I divulge that there was one cup (4 sticks) of butter, then let's agree to not pursue those details further.
Like most mashed potato recipes, you need to fine tune the amount of liquid and butter based on the specific type of potatoes, and to how dryly or softly cooked they are. Plus personal preference. Here's a starting point, adjust from there.
Tom's Silky Mash
2 pounds russet or gold potatoes, peeled, cut into 2" pieces
--- Boil approx 10 minutes, until fork tender, let cool
4-6 tablespoons butter
--- Melt in a medium sized pot
1/2 cup cream
3/4 cup whole milk
--- Add to pot with butter and combine
--- Press potatoes through strainer. Do not compress potatoes together after they are pressed through.
--- Use a rubber spatula, add the butter milk mixture into the potatoes, a little at a time, folding gently.
--- Season liberally with salt and fresh ground pepper