Preheat the oven to 350°F. Grease two heavy large baking sheets. Whisk the first 6 ingredients to blend in a medium bowl. Using an electric mixer beat the butter and sugar until smooth and light. Beat in the eggs, then the pumpkin. Mix in the dry ingredients and 1 cup pecans. Drop the dough onto prepared baking sheets by rounded tablespoonfuls, spacing evenly. Bake until the cookies are golden brown, about 12 minutes. Meanwhile: stir the powdered sugar and maple syrup to blend in a small bowl, adding additional maple syrup by teaspoonfuls if necessary until mixture is easily spreadable. Carefully spread the icing over a warm cookie and sprinkle with a few of the remaining pecans. Repeat until all the cookies are frosted; cool completely. Store the cookies in an airtight container and enjoy within 3 days.