1 Peel potatoes and place in a pot. Add enough water to cover, add salt and bring to a boil. Cook over medium heat until potatoes are knife-tender, 20-25 minutes.
2 Meanwhile, rinse the herbs, shake dry, pluck leaves and finely chop.
3 In a small pot, heat buttermilk with herbs over medium heat (do not let boil or buttermilk will curdle).
4 Drain the potatoes, return to pot and let stand until steam escapes.
5 Mash potatoes with a potato masher or pass through a potato ricer.
6 Add buttermilk mixture to potatoes and season with salt, pepper and freshly grated nutmeg. Stir until smooth and combined. Serve immediately with the butter.