Preheat the oven to 350°F. Scrub the potatoes clean with a vegetable brush under cold running water.
Place the whole potatoes in a large (8- to 10-quart) stockpot or Dutch oven and cover with cold water by about 1 inch LOVE NOTE:Starting potatoes in cold water helps them cook more evenly because the whole potato has a chance to warm up as the water warms. If you drop potatoes into boiling water, the outsides will cook much faster than the insides. Don’t be tempted to use hot tap water to speed up the process. No matter how old or new your plumbing is, most systems contain lead at some level, and hot water can leach the lead out of the pipes and into your cooking pot where it doesn’t boil away.Place pot over high heat and bring to a boil (put the lid on the pot to make the water go faster -- just make sure you remove it when the water begins to boil or it could boil over). Lower the heat and simmer uncovered until the potatoes are fork-tender (a fork should be able to slide in and out very easily), about 30 minutes (better to slightly overcook than slightly undercook). When the potatoes are tender, drain in a colander set in the sink. Pour the potatoes out in a single layer on a rimmed baking sheet. Transfer to the oven and bake for about 8 minutes (to dry out excess moisture), but do not allow them to brownLOVE NOTE: Strange as it may seem, the dryer the potatoes, the creamier your smashers will be. That’s because the less water they soak up, the more half and half and butter they can absorb, making them extra rich and creamy. That’s why the potatoes are cooked whole, so they absorb less water, and why I like to pop them in the oven to dry out the excess moisture.
While the potatoes are drying out, place the butter in a warm spot to soften and the half-and-half in a small saucepan over low heat (adding warm cream to the potatoes will help keep them piping hot).
Return potatoes to the cooking pot (pour them into the pot or use tongs—they’re hot!) and smash them with a heavy duty wire whisk or a potato masher (don’t worry if they’re lumpy – that’s what makes them smashers.) Add the butter and warm half-and-half. Add additional half-and-half, if necessary, to achieve a creamy consistency. Season with salt and pepper.