Combine the butter, sugar, egg, vanilla extract and pumpkin in a large bowl; mix well.
Next, add the remaining ingredients and mix until the dough is formed; then wrap in plastic wrap and refrigerate for at least 1 hour or overnight.
Preheat oven to 350 degrees F.
Scoop cookies onto a cookie sheet using a medium scoop (approx. 1 1/2 tbsp.) 2-inches apart; then press down on the tops to even out the dough. Bake 10-12 minutes or until the bottoms are light brown and the tops have puffed up.
*Allow for an additional 1 hour refrigeration time before baking.