Boil sweet potatoes: Place sweet potatoes in medium pot, cover with water. Bring to a boil, add salt (and thyme, if using) and simmer until fork-tender, about 8-10 minutes.
Drain and steam: Drain the potatoes well, then put them back into pot over lowest heat setting. Cook until potatoes look dry, stirring constantly, to steam off any excess water.
Mash: Add butter, honey, cinnamon, nutmeg, pepper (and more salt, if desired). Mash with a potato masher until creamy. Check for seasoning, then serve hot.
