Preheat the oven to 400 degrees F.
Wrap the potatoes in foil and bake until easily pierced with a knife, 45 minutes to 1 hour. Unwrap and set aside to cool.
Add the butter, sugar, chile powder, salt and pepper to a medium bowl and vigorously stir until thoroughly mixed.
Split open the tops of the sweet potatoes, add a dollop of the spiced butter and finish with some toasted pecans on top.