In a medium mixing bowl, whisk together the dairy-free milk and apple cider vinegar. Set aside for 5 to 10 minutes. This is your dairy-free “buttermilk.”
In a separate large bowl or bowl of a stand mixer, combine the quinoa flour, white rice flour, coconut sugar, oat flour, tapioca flour, pumpkin pie spice, baking powder, baking soda, and sea salt. Stir to blend.
To the bowl with the dairy-free buttermilk, whisk in the eggs, pumpkin puree, maple syrup, and vanilla extract until creamy.
Pour the wet ingredients into the bowl with the flour mixture, and beat until a batter is formed. Allow the batter to rest for 30 minutes.
Meanwhile, preheat your oven to 350 degrees F. Line a muffin tin with cupcake liners.
Transfer the batter into the muffin tin, filling each liner ⅔ to ¾ of the way full. Bake for 24 to 25 minutes until a toothpick inserted comes out clean. Allow the muffins to cool for about 10 minutes in the muffin tin before transferring to a wire rack to cool completely.
Once cooled, make the monk fruit glaze (if using). In a small mixing bowl, combine the powdered monk fruit, dairy-free milk, and vanilla extract. Whisk until creamy. Use a spoon to drizzle the glaze on top of each muffin. Enjoy!