Preheat oven to 350 degrees. Grease cookie sheets.
In a mixing bowl, sift together flour, baking soda and salt. Set aside.
In a large mixing bowl, cream together butter and brown sugar with mixer. Add whole egg, additional yolk, vanilla and maple flavoring. Mixture will be creamy. Add dry ingredients and mix thoroughly. Dough will be soft and may be chilled for easy handling, if needed.
Arrange pecans in groups of 3 or 5 on prepared cookie sheets to resemble head and legs of turtle. Using a rounded teaspoonful of dough, roll into balls, and dip bottom of balls into unbeaten egg white. Press lightly onto nuts so tips of nuts will show when cookie is baked. Bake in preheated oven for 10 to 13 minutes. Do not over bake.
While cookies are baking, combine chocolate, milk and butter in a microwave-safe bowl and melt until smooth. Add confectioners' sugar and beat until glossy. If too soft, add more confectioners' sugar until it is of spreadable consistency.
Transfer baked cookies to wire racks and cool. When cooled, spread frosting over tops of each cookie. Allow frosting to set before storing. Makes 3 to 4 dozen cookies. Enjoy!