Mix the dry ingredients (flour, baking powder, salt, and cinnamon) together in a medium-sized mixing bowl. Set it aside when done.
In a separate large mixing bowl (or stand mixer) blend the butter and sugar together until it has a light and fluffy consistency. It normally takes a couple of minutes to achieve this consistency.
Add the pumpkin puree and egg. Blend them together well but avoid overmixing.
Gradually blend in the flour mixture until it's combined.
Cover the cookie dough and toss it in the fridge for at least an hour. This helps to make it easier to handle later and also intensifies the flavors.
While the cookie dough is resting, preheat the oven to 350°F.
Line your baking sheets with parchment paper and once your dough is ready, remove it from the fridge. Roll it into balls about 2 tablespoons in size. Dip and roll each ball into the sugar-cinnamon mix.
Place the dough balls on the baking sheet. Space them about 2 inches apart.
Press down slightly with your palm to flatten them a little. Put them in the oven and bake for 10-12 minutes or until the edges are golden.
Remove the cookies from the oven and let them cool off for about 5-10 minutes. Then, transfer them to a wire rack to completely cool. Enjoy!