Dice sweet potato and place in a medium saucepan of boiling water. Cook until tender but firm. Drain and rinse in cool water. Return to saucepan and mash.
In a medium bowl, sift together flour, baking powder, salt, nutmeg, cinnamon and brown sugar. Add chopped pecans and stir.
In another bowl, mix together eggs, milk, sweet potatoes and melted butter. Add wet mixture to dry mixture and stir well to form a batter.
Preheat a lightly greased griddle over medium heat. Drop 1/4 cup of batter at a time into the griddle. When bubbles begin to surface, flip pancake and cook the other side until golden brown. Repeat, using remaining batter.
Place cream in a large bowl. With a hand mixer, beat until just before stiff peaks. Add sugar and vanilla. Then beat until stiff peaks form. Top pancakes with topping and pecan halves.