Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
In a large bowl, cream together the melted butter and granulated sugar until smooth. Beat in the eggs one at a time, then stir in the pumpkin puree and vanilla extract.
In a separate bowl, whisk together the gluten-free flour blend, baking soda, salt, cinnamon, nutmeg, and ginger.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Spread the batter evenly into the prepared baking pan.
Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Let the bars cool completely in the pan before frosting.
While the bars are cooling, prepare the cream cheese frosting. In a medium bowl, beat together the softened cream cheese and softened butter until smooth and creamy.
Gradually add the powdered sugar, beating until well combined and fluffy. Stir in the vanilla extract.
Spread the cream cheese frosting evenly over the cooled pumpkin bars.
Cut into bars and serve.
Notes
Store leftover bars in an airtight container in the refrigerator for up to 3 days.