Pour apple cider/juice into small pot over high heat until it boils. Then reduce heat to simmer until you have about 1/2 cup of cider/juice left (~20 mins).
Set reduced cider/juice aside to cool.
Preheat oven to 350°F. Grease baking pan with vegan butter, oil, non-stick spray.
In a large bowl, whisk together flour, baking soda, baking powder, cinnamon, and salt.
In a separate large bowl, whisk together butter, sugar, non-dairy milk, apple cider vinegar, applesauce, and vanilla extract.
Pour wet ingredients into bowl of dry ingredients. Add cooled apple cider/juice. Whisk everything together.
Spoon or pipe batter into baking pan. Place the pan in the oven for about 10-12 minutes.
While donuts are cooling, mix together sugar and cinnamon for topping.
Dip donuts in melted butter and then in cinnamon sugar on both sides.
Notes
Equipment Small pot 2 large bowls Whisk Spatula Donut baking pan Spoon Optional: Piping bag or large plastic baggie Optional: Standmixer or handmixer