I've been making these mashed potatoes for several years now and it may just be the best holiday mashed potato recipe EVER! I'd love to take credit but this yumminess comes from Gourmet Magazine circa 2005. Enjoy!!! I'll be bringing these for Thanksgiving.
5 lb yellow-fleshed potatoes such as Yukon Gold, peeled and cut into 1-inch pieces
1 tablespoon salt
1 cup whole milk
1/2 cup sour cream
1 1/2 sticks (3/4 cup) unsalted butter
2 bunches scallions, cut crosswise into 1/2-inch pieces
1/2 teaspoon black pepper
Cover potatoes with cold water by 2 inches in a 5- to 6-quart heavy pot and add 1 1/2 teaspoons salt. Bring to a boil, then reduce heat and simmer, uncovered, until potatoes are tender, 10 to 15 minutes.
Drain potatoes in a colander, then return to pot and cook over moderate heat, shaking pot occasionally, until dry, 1 to 2 minutes. Mash hot potatoes with masher or force through food mill into another pot, then cover to keep warm.
Bring milk with remaining 1 1/2 teaspoons salt just to a boil in a 1-quart saucepan, then remove from heat and stir into potatoes until combined. Stir in sour cream, then cover and keep warm.
Cook butter in a 12-inch heavy skillet over moderately high heat, stirring frequently and scraping up brown bits, until foam subsides and butter is golden brown, about 8 minutes. Add scallions and pepper and cook, stirring, until slightly softened, about 2 minutes. Fold butter mixture into mashed potatoes and season with salt.
Keri's tip - if you've never made brown butter before just hang in there and keep stirring, it will happen. For the first 8 minutes you're going to be asking yourself, is it done? No. You'll know when it's done. It gets really brown and starts turning into bits. Trust me.
Mashed potatoes can be made 1 day ahead and cooled, uncovered, then chilled, covered. (Scallions may discolor slightly when potatoes are made ahead.) Reheat in a microwave or in a heavy pot over moderate heat, stirring.