Preheat the oven to 350 degrees. Grease a 9-inch by 13-inch baking pan or use parchment paper to line your baking dish. Use a hand or stand mixer to cream the butter and sugar until smooth and creamy. Add the egg and vanilla until thoroughly mixed. Add the pumpkin puree and mix, it will have a curdled look to it. It's perfect. Grab a bowl and whisk the flour, cinnamon, baking soda, and salt together until thoroughly mixed and fluffy. Now, add the dry ingredients to the wet mixture and mix until smooth. Fold in the chocolate chips gently Spread the mixture evenly in your greased baking pan. Bake for 35-45 minutes or until a toothpick inserted in the center of the bars comes out clean. Cool on a cooling rack and cut when completely cool. Enjoy. These are so moist, they will be a family favorite.