In a large bowl, whisk to combine the rice flour, sorghum flour, potato starch, dry milk powder, tapioca starch, baking powder, pumpkin pie spice, xanthan gum, salt, and mini chocolate chips.
In a smaller bowl, whisk together the pumpkin puree, brown sugar, oil, eggs, and vanilla.
Pour the wet ingredients into the dry ingredients and stir to combine.
Spoon the batter into a large resealable bag. Cut a hole in one of the corners of the bag, and pipe the batter into the prepared doughnut pans.
Bake in preheated oven for 12-14 minutes, or until the top of the doughnut bounces back when gently pressed on.
Let the doughnuts sit in the pan for 5 minutes before removing them.
Mix together 1/3 cup granulated sugar and 1 teaspoon ground cinnamon. While the doughnut is still warm, gently toss them with the sugar/cinnamon mixture before placing them on a wire cooling rack. (The sugar mixture will only stick on the part of the doughnut that was in the pan.)
These can be served warm, or stored in an airtight container once cooled. The sugar/cinnamon mixture will dissolve once they are stored in a container.
Although this recipe is for doughnuts using a doughnut pan, you can always use a muffin or mini muffin pan instead. You may need to adjust the baking time according to the size of the pan.
Recipe by The Baking Beauties at http://www.thebakingbeauties.com/2013/10/gluten-free-baked-pumpkin-chocolate-chip-doughnuts.html