Preheat oven to 350 degrees. Prep the donut pan with baking spray.
Combine flour, baking powder, salt, cinnamon and sugar.
In a large bowl add the egg, pumpkin, milk, vanilla and oil.
Whisk the wet ingredients together.
Add the dry ingredients into the wet ingredients.
Gently mix the ingredients together.
Do not over-mix the donuts.
Spoon the batter into a pastry bag with a large tip.
Squeeze the batter into a treated donut pan.
Bake for 8 minutes at 350 degrees.
Allow to cool briefly before moving to a wire rack to cool completely.
Add unsalted butter in a double boiler until the butter melts.
Add sugar and heavy whipping cream in a bowl, stir to combine.
Add the sugar and cream to the double boiler.
Whisk to combine.
Continue to stir and bring to a boil.
Remove from heat.
Pour into a bowl allowing to cool slightly.
Dip doughnuts in the glaze and place on a pan lined with parchment