Preheat your oven to 400 degrees F. This step is crucial as it ensures that our donut holes bake evenly and achieve that perfect golden color.
In a large mixing bowl, combine all the dry ingredients: all-purpose flour, cornstarch, baking powder, and a pinch of salt. Whisk them together until well incorporated. This helps to evenly distribute the baking powder.
In another bowl, whisk together the wet ingredients: buttermilk, neutral oil, large egg, and vanilla. Make sure everything is well mixed, as this will create a uniform batter.
Gently pour the wet ingredients into the dry ingredients. Stir until just combined. Be careful not to overmix; you want the batter to remain light and airy.
Scoop the batter into a mini muffin pan, filling each cavity about three-quarters full. This ensures they have enough room to rise without overflowing.
Place the muffin pan in the preheated oven and bake for about 9 to 12 minutes. Keep an eye on them! They should puff up and bounce back when lightly pressed in the center.
Once baked, allow the donut holes to cool in the pan for a few minutes. Then gently remove them and place them on a wire rack.
While the donut holes are cooling, mix together the cinnamon and remaining sugar in a small bowl.
Brush the tops of each donut hole with melted butter and dip them in the cinnamon sugar mixture. This will give them that classic sweet crust we all love.
If you want to make the icing, mix together the cream cheese, confectioner’s sugar, vanilla extract, and milk in a bowl. Adjust the consistency as needed, adding more milk or cream cheese until it’s just right.
Drizzle the icing over the tops of the donut holes as a finishing touch. They'll look irresistible!