Add 1 in. of water to a large saucepan; add carrots. Bring to a boil. Reduce heat; cover and cook for 9-11 minutes or until tender. Drain and cool.
Place the carrots, milk, eggs, pumpkin pie spice, cinnamon and salt in a blender. Cover and process until pureed; process 1 minute longer. Pour into pastry shell. Combine the pecans, brown sugar and butter; sprinkle over filling.
Bake at 375° for 45-50 minutes or until a knife inserted near the center comes out clean and edges are browned. (Cover edges of crust with foil during the last 20 minutes to prevent overbrowning if necessary.) Cool on a wire rack. Refrigerate leftovers.