Preheat your oven to 350℉. Use a nonstick spray to prep your muffin tin.
In a bowl, whisk together the flour, pumpkin pie spice, ½ tsp cinnamon, and baking powder. Make a well in the center of this for the liquid ingredients and set aside.
In another bowl, whisk the pumpkin puree, milk, brown sugar, oil, egg, and vanilla. Mix it until fully combined and smooth. Pour this mix into the well in the dry ingredients and stir it until it just comes together.
Using a cookie scoop or spoon, fill the muffin wells about halfway up each. This helps them stay donut holes rather than mini muffins.
Bake for 12 minutes, or until a toothpick comes out clean. Pull them from the oven and let them cool for a few minutes, then move to a cooling rack to finish cooling.
Melt your butter and in another bowl, mix in the cinnamon and sugar. Dip each donut hole in butter, then roll in cinnamon-sugar to coat. Enjoy!