Pre-heat the oven to 350 F. Grease a silicone donut mold with baking spray and set aside
Begin by combining the dry ingredients in a separate bowl (flour, cinnamon, nutmeg, baking soda, baking powder, and salt).
In a large bowl, blend oil and sugar for a minute.
Add eggs one at a time, mixing after each addition. Add the butternut squash, vanilla extract, and mix.
With a piping bag, fill the donut pan about 2/3 full. Bake for 10-15 minutes in the preheated oven, or until golden brown and when a toothpick inserted in the middle comes out clean.
Once out of the oven for a minute, take them out of the tin and transfer them to a wire rack.
For the cinnamon sugar coating, combine granulated sugar and cinnamon in a bowl. Melt butter for coating.
Dip the warm donuts in melted butter and coat them entirely with the cinnamon sugar mixture.