Wash and peel the sweet potatoes
Cut them into even chunks
Place the chunks in a pot and cover with water
Add a pinch of salt
Bring to a boil
Cook until the sweet potatoes are very tender
Drain the water
Return the sweet potatoes to the pot
Add butter
Add milk or cream
Mash until smooth
Season with salt and pepper
Add cinnamon or nutmeg if desired
Serve warm