Use a hand or stand mixer to beat butter until smooth and light. Then add 1 cup of sugar, beat to incorporate and set aside.
Separate yolks and whites from eggs.
Use a hand mixer to beat yolks until light (around 2 minutes), then add 1 cup of sugar and vanilla and continue beating until well incorporated.
Combine egg/sugar/vanilla mixture with butter/sugar mixture in stand mixer.
Add pumpkin puree to the butter/sugar/egg/vanilla mixture and combine well.. Set aside.
Beat egg whites until stiff. Then fold them into the butter/egg/sugar/pumpkin mixture.
In a separate bowl, combine your dry ingredients: flour, baking soda and pumpkin pie spice.
To the egg/butter/sugar/pumpkin mixture, begin adding the flour/baking powder/pumpkin pie spice mixture, 1/2 cup at a time. Once all 6 cups have been added and well incorporated, check the consistency of the dough. The dough should be smooth and not too sticky so that you are able to easily roll and mold it by hand. Add additional flour, if needed, 1/4 cup at a time, until reaching the desired consistency.
At this time, preheat oven to 325 degrees F. On a large cutting board, roll a piece of dough 1" in diameter to about 8" long.
Fold the dough in half and twist to shape. Place on a greased cookie sheet.
Optional: Mix one egg with 1 tbsp of water. Use a pastry brush to lightly coat each cookie with the egg wash.
Bake for 25-30 minutes or until golden brown.