1. Preheat oven to 350°F and grease two 9x13-inch baking pans with nonstick spray.
2. In a large bowl, whisk together gluten-free flour, baking powder, baking soda, cinnamon, and salt.
3. In another bowl, whisk eggs, sugar, oil, and pumpkin puree until well combined.
4. Add dry ingredients to wet mixture and mix until just combined; batter will be liquidy.
5. Divide batter evenly between prepared pans.
6. Bake for 25 to 30 minutes, or until a toothpick inserted in the center comes out clean.
7. Cool cakes completely in pans before frosting.
8. For frosting, beat cream cheese, butter, vanilla, and powdered sugar together until smooth.
9. Spread frosting evenly over cooled pumpkin cakes.
10. Cut each pan into 12 squares and serve.