In a large mixing bowl, whisk together the flour, spices, baking soda and salt and set aside.
Using mixer, cream the butter, granulated sugar and brown sugar. Beat on medium speed until mixed together well.
Add in the egg, followed by the pumpkin and mix together well.
Using mixer on low, slowly add in the dry ingredients and mix until just combined. Don't overmix.
Fold in most of the chocolate chips until well distributed evenly. Save out 1/4 cup for the top of the bars.
Pour the batter into the lined baking pan and smooth until even.
Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Let cool completely in the pan, then use the parchment to lift out the bars and cut into squares.
Let blondies cool completely before frosting.