Preheat your oven to 350°F (175°C) and lightly grease a donut pan with vegan butter or oil.
In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, ground cinnamon, and salt until well combined.
In a separate bowl, whisk together the plant-based milk, unsweetened applesauce, melted coconut oil, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until just combined. Be careful not to overmix.
Spoon the donut batter into a piping bag or a resealable plastic bag with one corner snipped off. Pipe the batter into the prepared donut pan, filling each cavity about 2/3 full.
Bake the donuts for 12-15 minutes, or until a toothpick inserted into a donut comes out clean.
While the donuts are baking, prepare the cinnamon sugar coating. In a shallow bowl, combine the granulated sugar and ground cinnamon, mixing well.
Once the donuts are baked, remove them from the oven and allow them to cool in the pan for a few minutes. Then transfer them to a wire rack.
While the donuts are still warm, brush each donut with melted vegan butter or coconut oil, then roll them in the cinnamon sugar mixture until fully coated.