In a saucepan, melt the butter over medium heat. Add the milk and Velveeta cheese, stirring until the cheese is melted and the mixture is smooth.
Layer half of the sliced potatoes in a greased baking dish. Pour half of the cheese mixture over the potatoes. Repeat with the remaining potatoes and cheese mixture.
Season with salt and pepper.
Cover the baking dish with aluminum foil and bake for 45 minutes. Remove the foil and bake for an additional 15 minutes, or until the potatoes are tender and the top is golden brown.
Let it cool for a few minutes before serving.
Notes:
For extra flavor, you can add some chopped onions or garlic to the cheese mixture.