In a large bowl, combine the flour, brown sugar, baking powder and salt. In another bowl, combine the milk, butter, syrup, sour cream, egg , vanilla and maple extracts. Stir into the dry ingredients just until moistened. Fill greased or paper line muffin cups two thirds full.
For topping, combine the flour, sugar, nuts and cinnamon; cut in butter until crumbly. Sprinkle over batter. Bake at 400 F degrees for 16-20 minutes or until muffins test done. Cool for 5 minutes before removing from pans to wire racks.