Eggless Cinnamon Sugar Donuts (Baked)

Preheat the oven at 350° F. Grease the donut pan with non-stick oil spray or butter. Set aside.
Add white vinegar into milk, mix and let it stand for 5 minutes. This will be homemade buttermilk.
In a large mixing bowl, take all-purpose flour, sugar, baking powder, baking soda, salt, and cinnamon powder. Whisk until everything is well combined.
Add melted butter, vanilla extract, and prepared buttermilk. Mix with a spatula or wooden spoon until everything is just combined. Do not overmix. The batter will be thick.
Spoon the batter into the donut pan, filling up to halfway. Or, pour the batter into a large piping bag (without tip) or a large Ziploc bag. Cut the corner and fill the donut pan. The donuts will rise very well, so do not overfill the pan.
Bake the donuts at 350° F for 10 minutes or until edges are lightly brown.
Remove from the oven and allow to cool for two minutes into the pan. Then transfer the donuts onto a wire rack.
In a plate or bowl mix sugar and cinnamon powder. And in another bowl take the melted butter.
Brush each donut lightly with butter on all the sides and then dunk into cinnamon-sugar mixture and coat the donut well on all the sides.
Donuts are best served freshly made or on the same day. Keep the leftover in an airtight container for up to two days at room temperature.