Place peeled and chopped sweet potatoes in a large pot and cover with cold water by about an inch. Add a pinch of salt. Bring to a boil, then simmer until very tender, about 15–20 minutes. Drain well.
Melt butter in a small skillet over medium heat, swirling occasionally until the solids turn golden and nutty, about 4–6 minutes. Remove from heat to stop browning.
Return drained potatoes to the warm pot or a large bowl. Add cream, brown butter (or regular butter), cinnamon, nutmeg, and maple syrup if using. Mash with a potato masher or pass through a ricer for smoother texture. Season with salt and pepper, and thin with extra cream if needed.
Transfer to a serving bowl and top with toasted pecans, orange zest, or mini marshmallows as desired. Drizzle with reserved brown butter for extra flavor.
Notes
Do not overwork the potatoes to avoid a gluey texture—avoid food processors.
Warm your cream before adding for a silkier mash.
Make ahead: store in an airtight container for up to 2 days and reheat gently with a splash of cream.