In the meantime, peel the potatoes and cut them into large chunks. Keep them in cold water if there’s a long gap between cutting and cooking.
Season the boiling water with salt, add the potatoes and garlic cloves (not the confit cloves), and cook for 12 to 15 minutes or just until tender. Do not under- or overcook.
In the meantime, add the cream and butter to a separate pot and cook over low heat until the butter is melted and the mixture is hot.
Once the potatoes are cooked, drain them and return them to the pot.
Add in the garlic confit cloves and mash them using electric hand beaters or through a food mill.
Fold in the hot cream and butter, along with sour cream, salt, and white pepper.
Adjust the seasonings and serve with additional melted butter over top.
Notes
I know these potatoes are all about the garlic, but a chef once told me that any great mash should be 50% potatoes and 50% fat for the best flavor—so don’t skimp on the butter, cream, or sour cream, because that’s what makes this side dish truly mouthwatering. Add more flavor: When I'm feeling creative, I’ll fold fresh chopped chives, grated parmesan, or crumbled goat cheese into the mash.Soak the potatoes: If I’m prepping these a few hours before a big dinner, I will keep the peeled potato chunks submerged in a bowl of cold water to prevent browning.Don’t overboil: I boil the potatoes only until a knife slides through a piece with no resistance. Overboiling will cause them to absorb too much water and turn soggy. Best mashing techniques: I prefer to mash potatoes with a food mill or potato ricer, but a hand masher or electric hand beaters on a low setting work, too. Just be careful not to overmash the potatoes, or else they’ll turn to glue.Warm the dairy: You’ll never catch me pouring cold cream and butter into mashed potatoes. Warming them in advance creates an emulsion in the potatoes, making them silky-smooth.Make-Ahead: You can make these mashed potatoes up to 1 hour ahead—just keep them covered and warm over very low heat. They can also be made up to 1 day in advance and stored, covered, in the refrigerator, which helps the garlic flavor develop further.How to Store: Store the mashed potatoes in an airtight container in the refrigerator for 4 days. They can also be frozen and covered for up to 2 months. Thaw overnight in the fridge, then gently reheat before serving.How to Reheat: The best way to reheat cold mashed potatoes is in a saucepan over low heat with a splash of warm milk or a pat of butter. Stir occasionally until they’re warmed through.