In a large pot, fill ½ way with water and add ½ teaspoon sea salt.
Peel and slice the potatoes into 1" pieces. Put the cut potato pieces into the large pot of water as you peel and slice so they don't turn brown.
Be sure water covers the potatoes by 2 inches, on medium-high heat and bring to a boil.
Reduce to medium-low heat, cook the potatoes for 20 minutes until the potatoes are soft and fork tender.
Drain well in a colander. Discard the water.
In a small pan, heat the heavy cream on low (don't boil).
Hold the potato ricer over a large empty pot, and load the ricer full in batches and press all the potato pieces into the large pot. Or, mash the potatoes in the pot with a potato masher. If you want airy fluffy creamy mashed potatoes, the ricer is your friend. A masher will work, but it never gets all the little lumps out completely.
Add the heated heavy cream, 2 teaspoons sea salt, and ½ teaspoon pepper to the mashed potatoes, next drop all the small butter pieces into the hot potatoes and stir until combined and creamy.
Transfer to an oven-safe casserole dish and cover with the lid or aluminum foil. Keep in a warm oven or place in the refrigerator.
5 Ways to reheat and keep mashed potatoes warm:
Reheat in the oven: keep foil on mashed potatoes at 375 for 30-40 minutes
Reheat in a slow cooker, add a little cream and butter to keep them moist.
Place mashed potatoes in a zip lock bag, seal well and place carefully in a simmering pan of water
Place mashed potatoes in a heat-safe bowl over a pot of water.
Reheat the potatoes in a method you choose and keep hot on an electric warming tray or a heating pad covered with a towel.
If you want airy fluffy creamy mashed potatoes, the ricer is your friend. A masher will work, but it never gets all the little lumps out completely.