Preheat oven to 350°F and grease a donut pan really well with oil.
Add the flour, sugar, salt, baking powder and pumpkin spice to a bowl and whisk them together to combine.
To another small bowl or jug add the oil/nut butter and the milk and whisk them really well to combine. Add the pumpkin, vanilla and orange zest and whisk again.
Pour the liquid mixture into the dry ingredients and stir to combine. Don't over stir. Just enough that everything is combined and you can't see any dry flour.
Carefully spoon into the prepared donut pan. Fill almost to the top. I use a spoon to fill, then a clean finger to tidy up around the middle. If you want to be neat you could use a piping bag to pipe the batter in.
Bake for 13 - 15 minutes or until a tooth pick comes out clean.
Leave to cool just long enough that you can handle the pan and donuts without burning yourself, then turn them out onto a cooling rack.
Brush each donut with melted butter then dip into a bowl of sugar to coat. If you want to dip in sugar without using the melted butter be sure to do it while the donuts are still pretty hot as it will stick better.
NOTES
See the FAQs for a pumpkin spice alternative and for how to make the recipe if you don't have a donut pan. TO STORE - Once completely cool store donuts in an airtight container. They are best eaten the same day but will keep ok for a couple of days.