Preheat oven to 325 degrees and lightly grease your doughnut pans (set aside).
First, in a medium bowl, whisk together your dry ingredients. Flour, sugar, baking powder, salt, and cinnamon.
In another medium bowl, with a spoon or spatula, mix together your wet ingredients. Milk, egg, butter, vanilla extract.
Then, pour your wet mixture into your dry mixture, and mix until combined
Next, using an uncut piping bag, place the piping bag into a tall container or tumbler. Depending on the size of your bag, you may be able to pour all of your batter into the pag (or half at a time). Once filled, cut the tip off of the piping bag and fill the doughnut pans (recommended to make 1 full circle in each (try to not double as they will double in size in the oven).
Bake for 10-12 minutes. They are done when the doughnut bounces back with a finger touch test.
Once done, immediately remove from the pan and place on a cooling rack
At this point, you may need to refill your piping back and get your second batch. If not, wait till the doughnuts are completely cooled before glazing.
For the glaze, whisk together melted (and browned) butter, milk, vanilla extract and powdered sugar.
Lastly, taking the cooled doughnuts in your hand, dip them top first into the glaze until the glaze fully covers the top of the doughnut. Slowly turn back over and place them on the rack to set. Optional (after you dip, add your choice of sprinkle or decoration)