Peel and dice the sweet potatoes.
Add the sweet potatoes to a large pot and fill with water. Bring to a boil and cook until soft and fork tender, about 15 minutes. Drain and return the potatoes to a pot.
Use a potato masher and mash the potatoes.
Add the vegan butter, plant-based milk, maple syrup, salt, cinnamon, and nutmeg and continue to mash until completely smooth. NOTE: If you want your mashed sweet potatoes to be less sweet, add half the amount of maple syrup.
Optional: Use an immersion blender to get the potatoes extra smooth.
Taste and adjust the sweetness and salt to your preference.