Peel 3 large russet potatoes and cut them into large chunks. As you are cutting them put the chunks of potato in a large pan of cold salted water so they don't brown.
When the potatoes are all cut, drain and rinse the potatoes and add more cold water with a couple of teaspoons of salt.
Cooking Instructions
Bring the cold water with potatoes to a boil on medium high heat. Turn the heat down and bring the water to a gentle boil. You should have large bubbles popping open slowly, not rapidly. You don't want the potatoes tossing around the pan vigorously. They will fall apart.
When the potato chunks are tender enough to split with a fork, drain them in a colander and leave them in the colander to dry out for 3-5 minutes. The edges will start looking white and powdery. Drying the potatoes is what helps make fluffy and light mashed potatoes. Potatoes still full of water will get a gluey and pasty consistency when you mash them.
To evaporate any remaining moisture in the potatoes, put the empty pot back on a burner with the temperature at medium. When the pot is warm, add back the drained and dried potatoes. If you hear sizzling it will be the remaining water evaporating from the potatoes. Keep moving the potatoes around in the pan. When the sizzle stops, you are ready to start mashing.
Keep the heat on medium as you mash. Once you have gotten all the potatoes mashed up, start mashing the butter in. When the butter has melted start adding milk, a little at a time. Each time you add a little milk, let it absorb as you continue to mash. Continue to mash and add milk until you have your potatoes at a consistency a bit thinner than you want to end up with. Then let let them sit on the heat for a couple of minutes to make sure they are warm enough to serve. The potatoes will continue to drink up the milk even after it has been mashed in and your mashed potatoes are going to thicken as they continue to warm.
Add the salt and pepper and whip the potatoes to the desired consistency. I use a fork to whip them up. You can use a food processor or hand mixer if you want them really smooth. I like a more rustic texture. The fork works great for me (and it's easier).
Now your mashed potatoes are ready to serve.
Serve immediately or leave pan covered on warm for a short time. Add more milk and whip it in if your mashed potatoes have stiffened up. Mix consistently to prevent the mashed potatoes from burning on the bottom.