Although it seems like a simple, homey side, mashed potatoes are surprisingly difficult to get right. I learned the secret to making perfect mashed potatoes in Ireland, and the Irish certainly know their way around spuds. I am going to share it with you here.
Great mash begins with using the right kind of potatoes. There are two kinds — floury and waxy — and they are not interchangeable. The waxy potatoes are small, new potatoes that are perfect for recipes where the potato needs to hold its shape such as potato salad. They are also good boiled or pan roasted. For mashed potatoes, choose a starchy potato — in America that would be a russet (sometimes labeled baking potatoes in the supermarket) or a Yukon Gold. Three large potatoes will make enough mashed potatoes for four people. You will also need half a cup of whole milk or cream, two tablespoons of butter and salt and pepper.
Select potatoes that are unblemished and hard as rocks. I prefer to buy them loose rather than in plastic bags because it’s easier to inspect them for blemishes or green spots.
Peel the potatoes and cut them into uniform quarters. It’s important that the potato pieces are all the same size so they cook at the same time.
Wash the potato quarters and place them into a pot that is large enough for all the potato pieces to fit in a single layer. Add enough cold water to cover the potatoes by half an inch. Add a pinch of salt. Put the pot on the stove at a high heat to bring to a boil. When the water comes to a boil, turn the heat down and let the potatoes simmer uncovered for about 20 minutes until the potato pieces are soft in the center when tested with a fork.
Drain the potatoes. Now pay attention, this is the secret to fluffy, floury mashed potatoes. Place the drained potatoes back into the pot, cover with a clean, cotton tea towel, cover the pot and place it back on a very low heat for about five minutes to dry out the potatoes.
While the potatoes are drying, heat cream or whole milk and butter in a saucepan. Warm the cream/butter mixture until the butter melts, but don’t let it come to a boil.
Turn off the heat under the potatoes. Gradually add the heated cream and butter mixture — you may not need it all. Mash the potatoes by hand with a potato masher — do not use a hand mixer or stick blender — or worst of all, a stand mixer. All of them will turn the starch in the potatoes to glue. When the potatoes are mashed, taste them and season them. Since the potatoes were cooked in salt, you may only need to add pepper. If serving the mashed potatoes family-style in a large bowl, make a well in the center of the potatoes and add two tablespoons of butter.