Preheat oven to 350°F. Spray a donut pan with nonstick baking spray or grease it with oil.
In a large bowl, whisk the flour, baking powder, baking soda, cocoa powder, and salt. Set aside.
In a separate bowl, mash the avocado until smooth. Add in milk, maple syrup, vanilla, and apple cider vinegar. Mix until combined, making sure there are no avocado lumps.
Pour the mixture into the dry ingredients and mix just until combined.
Use a spoon or a piping bag to fill donut cavities with batter 3/4 way full.
Bake for 16-18 minutes or until a toothpick comes out clean. Allow to cool slightly before removing from pan. Place on a wire rack to cool completely.
For the frosting, in a medium bowl, mash avocado with butter until combined. Beat in vanilla. Add powdered sugar and mix until smooth. Add more powdered sugar, if needed.
Top the cooled donuts with frosting and chocolate sprinkles.