Preheat oven to 350 degrees F. Line baking sheets with parchment paper if baking immediately, or skip this step of you plan on chilling the dough.
Finely chop ½ cup of the walnuts, then set aside both the finely chopped and remaining ¼ cup chopped walnuts.
In a large bowl, beat granulated sugar, brown sugar and butter with an electric mixer until blended. Add pumpkin and maple syrup. Mix well. Beat in flour, pumpkin pie spice, ground cinnamon, baking soda, and salt until blended. Stir in the oats, cranberries, pepitas and reserved ½ cup finely chopped walnuts. Mix well.
Drop batter by quarter cupfuls onto dinner plates lined with plastic wrap. Press into 3 inch rounds and chill until ready to bake. Alternatively,drop batter by quarter cupfuls onto parchment lined baking sheets. Spread each round with a metal spatula to make a 3 inch round. Sprinkle cookie with about 1 ½ teaspoons chopped walnuts.
Bake 15 to 17 minutes or until edges are set.