Bake potatoes at 400° for 1 hour or until tender; peel. Reduce oven temperature to 350°.
Beat potatoes, 1/4 cup brown sugar, next three ingredients, and 1/4 tsp. cinnamon in a large bowl at medium speed with an electric mixer until smooth. Spoon mixture into a 13- x 9-inch baking dish coated with cooking spray.
Combine chopped pecans, orange rind, remaining 1/4 cup brown sugar, and remaining 1/2 tsp. cinnamon; sprinkle evenly over potato mixture.
Bake at 350° for 20 minutes or until thoroughly heated.
Note: Prepare sweet potatoes a day in advance, if desired. Spoon into a 13- x 9-inch baking dish (do not add topping), cover with plastic wrap, and refrigerate. Remove potatoes from refrigerator, and let stand 20 minutes at room temperature. Sprinkle pecan mixture evenly over potatoes, and bake at 350° for 25 to 30 minutes or until thoroughly heated.