Peel and evenly cube the potatoes into medium chunks (about 1.5” - 2” / 3cm - 5cm each.) Place cut up potatoes in large saucepan and cover with water by about 1/2” / 1cm and season with about 1/2 teaspoon of salt. I prefer to use a sauce pan that won’t be damaged by a hand mixer because I mix them right in the pan. If you don’t have one, then you’ll have mix them in a separate bowl. Boil for 5-7 minutes or until potatoes pierce easily with a fork. Drain the water from the pan Immediately! * See note below.
Meanwhile, heat milk and butter in a small sauce pan on low. Do not boil. This is optional, but will help keep your potatoes warm. Adding cold milk and butter, will cool your mashed potatoes down. You can also heat butter and milk in a large measuring cup in the microwave.
Add seasonings, and mix in the pan with hand mixer on high until light and fluffy. Add more milk or butter if needed, but do so in small amounts so your potatoes don’t get runny. You can keep them warm on the stove or in the oven at 225°F/105°C/Gas Mark 1/4 for quite a while.
Top with more melted butter if you’d like then serve, or put the lid on and refrigerate.
Reheating in the oven:
Take Your mashed potatoes out of the refrigerator at least 2 hours before you plan to serve and let them gently come to room temperature.
Preheat oven to 350°F/165°C/Gas Mark 3
Cover mashed potatoes with oven proof lid or foil and place them in the oven on center rack. Cook for about 15-20 minutes. Stir them gently just so they can cook evenly. Cover and cook for an additional 15-20 depending on how many you’re reheating. Stir them again and serve, or keep warm in the oven at 225°F/105°C/Gas Mark 1/4. I find that stirring with a fork instead of a spoon helps keep them fluffy.
In a microwave:
Cover potatoes with plastic wrap and cook on 20% to 30% power for a couple minutes. Repeat for one minute, stir and continue until they are heated through. The idea is to get them warm slowly. Remeber the fork to keep them fluffy.
Never let your potatoes sit in the water after they are boiled or they will not have the right texture later. They will start to soak up all that water and disintegrate. If you’re not ready to mix them, just drain, cover with a lid and set aside.