Preheat oven to 350 degrees (F). Generously grease a doughnut pan and set aside.
In a large bowl whisk together the dry ingredients. In a separate bowl whisk together the buttermilk, melted butter, vanilla, and egg. Gently fold the wet mixture into the dry mixture - don't over mix! Fold in red food coloring and stir until combined.
Spoon mixture into prepared doughnut pan, and bake for 10 minutes, or until the doughnuts spring back when lightly pressed. Allow doughnuts to cool a few minutes in the pan before transferring to a wire wrack to cool for a few more minutes.
For the cream cheese frosting:
In the bowl of a stand-mixer fitted with the paddle attachment, or in a large bowl using an electric handheld mixer, beat the cream cheese, butter, and vanilla extract on medium-high speed until completely smooth; about 2 minutes. Reduce the speed to low and gradually add the sifted confectioners' sugar. Add in the milk. Once the milk is combined beat frosting on high-speed for 1-2 minutes.