Mix 1.5 cups self-raising flour and ¾ cup plant-based vanilla yogurt in a bowl until a soft, sticky dough forms. In case your dough feels too liquidy, add some more dough to balance it out. If the dough feels too dry, add a bit more yogurt. Your dough will be sticky though.
Take the dough out on to a floured surface and lightly knead the dough gently—just enough to bring it together. Don’t overdo it; we’re looking for soft and fluffy donuts, not chewy ones. I normally oil my hands so that it gets easier to handle the dough.
Roll out the dough to cylinder shapes and then cut them into 3-4 parts. I got 2 cylinders out of the this dough. Join the ends of each cylinder to form a donut. Repeat this for all.
Preheat air fryer to 180C or 360F for three minutes. Arrange your donuts in a single layer after lightly brushing them with vegan butter. Leave enough space between them so that they can puff up.
Air fry at 180C or 360F for about 5–7 minutes. This will depend upon the size and thickness of your donuts and the type of your air fryer.
Your donuts will not get too brown like the fried version but will be golden outside and will feel fluffy when pressed lightly. Don't air fry them more for more browning because they will end up getting dense.
Take them out and lightly dip or brush them into the melted vegan butter, making sure they are fully coated. Then, roll them in the cinnamon sugar mixture so that they are nicely coated.
Not all of the cinnamon sugar will be used up. You will love the buttery, sugary goodness of this indulgence of air fryer donuts.