Preheat your oven to 350°F (175°C). Grease a 10 x 15-inch baking pan with gluten-free cooking spray, or line the pan with parchment paper to prevent sticking. Preparing your pan ahead of time will make it much easier to remove the pumpkin bars later.

In a large bowl, combine the pure pumpkin from the can, baking powder, baking soda, salt, ground cinnamon, pumpkin pie spice, and vanilla extract. Stir until everything is fully incorporated, ensuring the spices are evenly distributed.

Add the white sugar and light brown sugar to the pumpkin mixture. Stir until the sugars are incorporated and the mixture is smooth. Next, add the eggs one at a time, mixing well after each addition until the mixture is fully combined.

Gradually add the gluten-free all-purpose flour to the wet mixture, mixing until no streaks remain and you have a thick, smooth batter. Then add the vegetable oil (or the mixture of applesauce and oil if desired) and mix until well blended. If I have applesauce on hand, I like to substitute half the oil for a lighter option without sacrificing moisture.

Pour the batter evenly into the prepared baking pan, smoothing the top with a spatula. Place the pan in the preheated oven and bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Let the bars cool completely in the pan before frosting. I find chilling the bars slightly helps the frosting set up nicely.

In a large bowl, beat the softened cream cheese and softened butter together with an electric mixer until smooth and creamy. Add the vanilla extract and mix until combined. Gradually add the powdered sugar, continuing to beat until the frosting is completely smooth and fluffy.

Once the pumpkin bars are completely cooled, spread the cream cheese frosting from Step 6 evenly over the top. Cut into bars and serve. Store any leftovers in an airtight container in the refrigerator to keep them fresh.