Preheat your oven to 350°F (175°C). Grease and flour a baking pan.
In a large mixing bowl, whisk together the pumpkin puree, sugar, and vegetable oil until smooth.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In another bowl, combine the gluten-free flour blend, baking powder, baking soda, salt, cinnamon, and nutmeg.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Pour the batter into the prepared baking pan and smooth the top.
Bake for 45 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.