Crushed Potatoes With Leek-Peppercorn Butter

Drain the potatoes into a colander and leave in the sink to drain further. Wipe out the pot; no need to wash it. Add the butter to the pot and set over medium heat. Once it’s melted, add the leeks, season with salt to taste, and cook until they’re softened (the color should be bright green), 5 to 7 minutes. Add the peppercorns, stir to coat, then turn off the heat.