Wash and scrub sweet potatoes, then using a fork make several holes to allow steam to escape. Place on a foil lined baking sheet and bake for 40-50 minutes, or until easily pricked with a fork or knife. Allow to cool a few minutes, then slice each potato lengthwise.
Scoop out the centers and place in a medium size mixing bowl.
Add the butter, brown sugar, rosemary, cheese, salt and pepper and mix well.
Carefully add the potato mixture back to the skins equally.
For the topping, mix together the butter and Worcestershire sauce and drizzle over the halved potatoes.
Sprinkle with pecans and bake for 10-15 minutes, or until just starting to brown around the edges.