It's hard to improve upon the honest goodness of mashed potatoes, but here scallions and brown butter do the trick. The scallions provide sweetness, and the brown butter adds a beguiling nuttiness.
04Cook 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.