Place the potato cubes in a large pot and cover them with cold water.
Add a generous pinch of salt to the water.
Bring the water to a boil over high heat and then reduce the heat to maintain a gentle simmer.
Cook the potatoes for about 15-20 minutes or until they are fork-tender.
Drain the potatoes in a colander and let them sit for a minute or two to allow excess moisture to evaporate.
Return the drained potatoes to the hot pot to dry them out further. Place the pot back on the burner (turned off) for a minute, shaking it gently to prevent sticking.
In a small saucepan, melt the butter over low heat. Once melted, remove it from the heat.
In another small saucepan or in the microwave, warm the milk until it's hot but not boiling.
Using a potato masher or a ricer, mash the potatoes until they are mostly smooth and lump-free.
Pour the melted butter over the mashed potatoes and stir to combine.
Gradually add the warm milk to the potatoes, stirring as you go. Add enough milk to reach your desired creamy consistency.
Season with salt and freshly ground black pepper to taste. Be sure to taste as you go and adjust the seasoning as needed.
Transfer the creamy mashed potatoes to a serving bowl.
Garnish with chopped fresh chives or parsley if desired.
Serve hot, and enjoy the rich, creamy goodness!