In a medium bowl, mix flour, baking powder, cinnamon and salt.
In a large bowl, cream softened butter and sugar together and beat in egg.
Add milk and vanilla to large bowl with butter, then add the flour mixture, mixing until batter is thoroughly combined.
Spoon into a greased donut pan.
Bake for 12 minutes and remove from oven.
While donuts are still warm, dip in a mixture of cinnamon and sugar.
Video
Notes
You'll want to coat the donuts in the cinnamon sugar while they are still warm since it helps the sugar to stick on the donut.
My favorite way to eat these baked cinnamon donuts is while they are still warm. If you plan to let them cool a bit, you can place them on a wire rack.
This nutritional information is approximate and was calculated using online calculators. Your nutritional information may vary depending on numerous factors.