Prep oven and pans. Position a rack in the center of your oven. Preheat oven to 350°F (177°C). Spray 2 24-count mini muffin pans with non-stick spray
Combine dry ingredients. In a large bowl, whisk together the flour, baking powder, baking soda, salt, and pumpkin pie spice together until combined. Set aside.
Combine sugar and eggs. In a medium bowl, whisk the brown sugar, granulated sugar and eggs together until smooth and combined.
Add remaining wet ingredients. Whisk in the pumpkin, oil, milk, and vanilla until combined.
Stir in flour mixture. Pour the wet ingredients into the dry ingredients and stir until just combined. Do NOT overmix the batter.
Bake the muffins. Spoon the batter evenly into the cups , right up to the top is OK and will create nice tall muffins. Bake for about 12-14 minutes or until a toothpick inserted in the center comes out clean. Remove from the oven and cool in the pan for 5 minutes then transfer to a wire rack to cool completely.
Dip in butter and sugar. In a small bowl, melt the butter. In a second small whisk together sugar and cinnamon. Dip a muffin in the butter then roll in the cinnamon sugar. Repeat with remaining muffins. Serve and enjoy!