Peel the Yukon Gold potatoes and cut them into 1/2-inch chunks. This helps them cook evenly and absorb the milk.

Place the potato chunks in a large saucepan or Dutch oven. Add 5 cups of whole milk and 2 teaspoons of kosher salt. Bring the mixture to a gentle simmer over medium heat. Once simmering, reduce the heat to low and cook uncovered, stirring often, until the potatoes begin to fall apart and most of the milk is absorbed, about 40 to 50 minutes.

Remove the pan from the heat. Add the salted butter, cut into pieces, and use a potato masher to mash the potatoes into an almost-smooth puree. If you prefer a softer texture, you can add more milk to reach your desired consistency. I like to let the butter melt fully before mashing for the creamiest potatoes.

Taste the mashed potatoes and season with additional kosher salt and freshly ground black pepper as needed. Serve warm and enjoy.