1. Preheat oven to 350 degrees. Spray or grease with vegetable shortening donut pan(s).
2. Into a large bowl, sift together the flour, baking powder, baking soda, cocoa powder and salt; set aside.
3. In another large bowl, mix together the sugar and egg. Add the melted butter, melted chocolate, vanilla extract and buttermilk; mix well to thoroughly combine.
4. Gradually add the dry ingredients in the first bowl to the wet mixture, mixing just until combined.
5. With a spoon or a pastry bag, carefully fill prepared donut pan(s) with the batter, filling each opening about two-thirds full (or you could use a standard ice cream scoop, filling scant-level; dollop on each donut opening and with wet finger, open up the hole, pushing the batter to the sides evenly).
6. Bake for 12-15 minutes (donuts should spring back with touched lightly).
7. Cool completely on wire rack.
2 tablespoons water.
1 tablespoon buttermilk.
1/2 teaspoon vanilla extract.
2 cups powdered sugar.
With a wire whisk, combine all ingredients until smooth.
8. Dip the donut tops in the icing, letting excess fall back into the bowl (be careful not to let crumbs get in the icing). Let dipped donuts dry/set on rack.
In the alternative, you could use a homemade or canned cream cheese frosting to top the donuts.