Peel the potatoes carefully. Cut them into equal sizes so they cook evenly. This prevents some pieces from being mushy while others stay hard. Wash them in cold water.

Place potatoes in a large pot. Cover them with cold water. Add a generous pinch of salt. Bring to a boil, then simmer for about 15 to 20 minutes.

Check if the potatoes are tender with a fork. Drain them into a colander. Return the potatoes to the hot pot for one minute. This evaporates any remaining water.

While the potatoes dry, use a small saucepan. Heat the milk and half the butter together. Do not let it boil. Just keep it warm so the potatoes stay hot.

Pass the potatoes through a ricer into a bowl. A ricer makes them very fluffy. If you do not have one, use a hand masher. Avoid using a blender or mixer.

Slowly pour the warm milk mixture into the potatoes. Use a spatula to fold it in gently. Do not overmix, or the potatoes will become sticky like glue.

Add the remaining butter, salt, and pepper. Stir until the butter melts completely. Taste and add more salt if needed. Transfer to a warm bowl and serve immediately.