Remove tops from carrots and set aside in refrigerator until ready to serve. Peel carrots and cut into chunks. In 3-quart saucepan, place carrots and enough water to cover. Heat to boiling; reduce heat to medium. Cover; cook about 20 minutes or until soft. Drain; cool slightly.
Preheat oven to 350°F. Line a 9” x 13” baking dish with a single piece of heavy-duty aluminum foil that is longer than the pan by 3-inches on both ends. Grease the foil with butter or cooking spray.
In food processor, place carrots, butter, sugar, flour, baking powder, vanilla, salt, and eggs. Cover; process until pureed. Spoon mixture into the foil-lined pan. Carefully start to lift the sides of the foil to create the carrot shape, pinching to seal the pointed end of the carrot. Use thin strips of wood to square-up the sides of the carrot and hold in place with crumbled up pieces of foil.
[Alternatively, bake soufflé in a greased 2-quart casserole.].
In medium bowl, mix grated carrots, pecans, and brown sugar. Sprinkle evenly over carrot mixture.
Bake uncovered 55 to 65 minutes or until center is set and a knife inserted comes out clean.
Remove from oven and unmold soufflé onto serving platter. Insert reserved carrot tops in to the top of the carrot shape.