Peel and cut potatoes into 1 1/2 inch cubes and place into a large pot, the smaller you cut your potatoes the quicker they will cook. Add water to potatoes until they are just covered. Add 1 teaspoon salt to water. Cook the potatoes on medium-high heat for about 15 to 20 minutes or until potatoes are tender when pierced with a fork.
Drain potatoes in a colander and then place into a bowl. While the potatoes are cooking warm together the dairy. You can heat it together in the microwave or in a small saucepan on the stove. Mash potatoes either by hand with a potato masher, or blend until mostly smooth with a mixer.
Pour melted butter and milk mixture into mashed potatoes and stir until well combined. Adjust for seasonings and serve immediately. If you want to change up your mashed potatoes here are a few ideas. Add a couple of tablespoons of minced chives or sliced scallions make a wonderful addition.
You could also make loaded mashed potatoes by substituting the buttermilk for sour cream and adding 1/2 cup of cheddar cheese, 2 tablespoons of bacon bits for a loaded mashed potato. Serve them up special or in the traditional way they are going to taste so good when you make them homemade.