How to get very smooth, flat cooked potato pieces

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.

Tough question - there are a lot of non-scientific ways to measure small/medium/large potatoes and nobody seems to agree on exactly what weight each is. However, there are a few ways I identify large vs medium at home.

In my experience, a large potato is about the size you would get in a restaurant (I know, not very specific). That is, when I cook at home, the potatoes I purchase tend to be medium - round (not oval) and about the size of a tennis ball or baseball. When I'm at a restaurant their potatoes are noticeably larger, and generally more oval shaped it seems (closer to a sweet potato in shape and size), which makes them great for stuffing like for a loaded baked potato. Luckily most of the recipes I have at home that involve potatoes don't require precise measurement, so I just stick with my eyeball measurements and don't even bother weighing them.

I found a source online that says this:

According to Shape magazine, eatbetteramerica.com and prevention, a medium potato is the size of a computer mouse, so somewhat bigger than that.

And I think I can get behind that answer. I'd say your average computer mouse (like, one you would get with a new PC, not a fancy third-party mouse) is about the size of an average medium potato. Another way to eyeball: I'm a 30 year old male with hands that are neither very large or very small. The medium potatoes in this bag are about the size of a loose fist for me. So a large potato would be bigger than either of those things.

As for measurements, I have a bag of medium potatoes and it says they're 5.3 oz (150g) a piece. I weighed one and it was closer to 6.5oz (185g). Based on that I'd say a large potato would be anything over 8oz (225g), pushing as high as 12oz (340g).

I found a way to search online for this info: calories. By searching for "large potato calories" I was able to find pages with weights and measures:

• 3 to 4 1/4 inches in diameter
• 300 grams (about 10.5oz)

So, in short, it seems like I would consider these good numbers:

• Medium potato: 2 to 3" in diameter, 5-8oz (140-225g)
• Large potato: 3 to 4.25" in diameter, 8-12oz (225-340g)

Below is a picture of the medium potato from my bag, compared to some common household/kitchen items. The gift card is the size of a normal credit card, and the knife is a common steak knife from my utensil drawer. Apparently a medium potato is almost exactly the size of a 1 cup measure!