Peel the potatoes and cut them into 1-inch chunks. Rinse them under cold water to remove any excess starch.
Place the potatoes in a large pot and cover them with cold water. Bring the water to a boil over high heat, then reduce the heat to medium-low and simmer the potatoes until they’re fork-tender (about 15-20 minutes).
Drain the potatoes and return them to the pot. Add the butter and milk, then use a potato masher or hand mixer to mash the potatoes until they’re smooth and creamy. Be careful not to overmix, as this can make the potatoes gummy.
Add salt and pepper to taste, then give the potatoes a final stir to incorporate the seasoning.