Place potatoes in a large pot and cover with salted water. Bring to a boil. Reduce heat to medium-low, cover, and simmer until tender, 20 to 25 minutes.

Drain potatoes, then return to the pot. Turn heat to high and allow potatoes to dry for about 30 seconds. Turn off heat.

Mash potatoes with a potato masher twice around the pot, then add milk and butter. Continue to mash until smooth and fluffy. Whisk in salt and black pepper until evenly distributed, about 15 seconds.