Cream the butter and brown sugar together. Add the egg, maple syrup & vanilla and mix well. Combine the flour and baking soda and add to the creamed mixture and mix until well blended. If the dough is very soft, more flour can be added. Shape the dough into 1ʺ balls, roll in the white sugar and place on parchment lined cookie sheets. Bake at 350°F for 8 – 10 minutes. Remove from pans and cool on wire racks.