Preheat oven to 350°F. In medium bowl, whisk together flour, cocoa powder, baking soda and salt. In a large bowl, whisk together buttermilk, egg, granulated sugar, butter and vanilla extract. Add dry ingredients to wet ingredients and mix until just combined.
Place batter in ziploc bag and squeeze out air. Cut corner of bag. Spray 6-cup donut pan with non-stick spray. Pipe the batter evenly in the donut pan. It should make 10 so you will need to repeat.
Bake for 10-12 minutes or until stick comes clean. Let cool in pan for 5 minutes and remove and place on cooling rack for 5 to 10 minutes. Dip donuts in glaze.
Chocolate Glaze
For the glaze, whisk the sugar and cocoa powder in a shallow bowl. Slowly stir in milk and vanilla extract to make smooth, pourable glaze. Dip each donut in the glaze and place back on cooling rack. Top with sprinkles if desired. Allow glaze to set for 30 minutes before serving.
Notes
For extra chocolate, mix in ½ cup of mini chocolate chips into the batter.
You can spoon the batter into the donut pans, but the easiest way to get the batter in the pan is by using a pastry bag or Ziploc bag with the corner cut off.
Just like with any cake type batter that you make, you’ll know the donuts are done when a toothpick comes out clean.
Let the baked donuts cool completely before you dip them in the glaze.
If you are in a rush, place the donuts in the freezer after dipping in the glaze for 5 minutes to get it to set quicker.
Leftovers will store well in at room temperature for 1-2 days in an air-tight container.