Preheat your oven to 375°F (190°C). Line a standard 12-cup muffin tin with paper liners.
In a large bowl, whisk together the gluten-free flour, baking soda, baking powder, salt, cinnamon, ginger, and nutmeg.
In a separate medium bowl, vigorously whisk together the pumpkin puree, eggs, oil, brown sugar, milk, and vanilla extract until smooth and well-combined.
Pour the wet ingredients into the dry ingredients. Using a spatula, gently fold the two together until just combined. Be careful not to overmix; a few lumps are okay.
Divide the batter evenly among the prepared muffin cups, filling each about ¾ full.
Bake for 5 minutes at 375°F, then reduce the oven temperature to 350°F (175°C). Continue baking for another 15-20 minutes, or until the tops are springy to the touch and a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.
