Preheat the oven to 350F. Grease a donut pan with cooking spray.
In a large bowl, combine the gluten-free flour, brown sugar, baking soda, baking powder, salt, pumpkin pie spice and whisk together.
Add in melted vegan butter, pumpkin puree, almond milk, apple cider vinegar and vanilla. Whisk to combine.
Spoon the batter into the donut pan wells or pipe it with a pastry bag.
Bake at 350F for 10-12 minutes, until a toothpick inserted into the donut comes out clean.
Let cool for a few minutes and then turn donuts out onto wire rack.
Pour powdered sugar into a shallow bowl. Press donuts into the powdered sugar on both sides.
Best served the same day.