In another bowl, whisk together the buttermilk, melted butter, vanilla, and egg. Fold the wet mixture into the dry mixture.
Add drops of red food coloring and mix until you reach a desired color.
Transfer batter to a piping bag. Snip off the tip.
Bake for 10 minutes. Test with a toothpick.
Let the donuts cool on a wire rack.
For the Cream Cheese Glaze:
In a stand mixer fitted with a paddle attachment, beat together cream cheese and vanilla until smooth.
Add in sifted confectioners sugar and milk. Add milk until you reach a desired consistency.
Beat for about 5 minutes.
Dip donuts into frosting.
Sprinkle leftover crumbs onto glaze.
Video
Notes
If you don't use any food coloring they end up a dusty brownish pink with is beautiful in its own way but not in a way that photographs well... I had a bit of extra batter so I made a couple cupcakes and sacrificed one to crumble to a bit of contrast on top.
You can play around with the thickness of your glaze by adding milk slowly until you're pleased with the consistency. It will vary slightly based on how you pack your sugar, ambient humidity etc.
This glaze is amazing on basically everything so try it on your next bundt or pound cake.