Preheat oven to 190°C.
Place sweet potatoes on sheet tray and bake for 1 hour or until soft. Remove from oven and let stand until cool enough to handle.
Split potatoes and remove the flesh to a medium sized bowl, reserving skins. In another bowl, add brown sugar, and cream cheese and the all of the spices and mash with a fork or rubber spatula.
Add the butter and cream cheese mixture to the sweet potato flesh and fold in completely. Add the filling back to the potato skins and place on a half sheet tray. Bake for 15 minutes or until golden brown.