Preheat the oven to 425 degrees F. Spray/grease 5 muffin tin cups and set aside.
Add almond flour, oat flour, coconut flour, baking powder, 1 tsp. cinnamon, pumpkin pie spice, and salt to a large bowl and whisk to combine. Be sure to whisk out any large clumps of flour.
Add apple cider vinegar to a ½ cup measure. Fill the rest of the measure up with milk. Allow to sit for 5-10 minutes, or until it starts to curdle. This is your homemade buttermilk.
To your melted coconut oil, add nut butter, pumpkin puree, vanilla, and maple syrup and mix well to combine. Add “buttermilk,” and mix well to combine.
Add liquids to your dry ingredients and mix well until combined. The batter will be thick and fluffy.
In a small bowl, combine coconut sugar and remaining 1/2 tsp. cinnamon. Mix to combine.
Fill 5 muffin cups half way with batter. Sprinkle about 1/4 tsp. coconut sugar-cinnamon mixture on top, and then fill to the top of the muffin tin with the remaining batter. Top with the remaining coconut sugar-cinnamon mixture.
Bake for 5 minutes at 425 degrees F. WITHOUT OPENING THE OVEN DOOR, lower the oven temperature to 375 degrees F, and bake for an additional 13 minutes, or until a toothpick inserted into the middle comes out clean. This method gives these muffins optimum rising power.
Remove from oven and allow to sit in the muffin tin for 10 minutes. Remove muffins and place on a cooling rack to continue cooling.
Enjoy slathered with nut butter or drizzled with maple syrup!