Preheat your oven to 375 degrees Fahrenheit (190 degrees Celsius). Grease a medium 12-donut donut pan (or two if you have) with vegetable oil cooking spray or butter and set aside.
In a large bowl, whisk together the flour, cocoa, sugar, baking powder, and salt.
In a large glass measuring cup, measure the buttermilk.
Add the eggs and vegetable oil to the buttermilk and whisk with a fork to combine and break up the eggs.
Add the red food colouring paste and mix well with the wet ingredients until completely blended.
Add the wet ingredients to the dry ingredients and mix together gently with a rubber spatula just until any streaks of flour disappear. Over-mixing can make the donuts tough and rubbery, so mix gently and only as much as you need to.
Add the batter to a large piping bag and pipe the donuts into the donut pan cavities only about 1/2 full.
Bake at 375 degrees Fahrenheit for about 8-11 minutes, or until the donuts are no longer shiny on top and a toothpick inserted into one of the donuts comes out clean.
Cool in the donut pan for about 5 minutes before removing to a wire rack to cool. Repeat the steps for the next 12 donuts (this recipe makes 24 mini donuts).
Once cooled slightly, dip the donuts in powdered sugar (use a light spritz of vegetable oil spray on the donuts if the powdered sugar needs help sticking!) and enjoy!