Preheat the oven to 350 degrees.
Spray enough doughnut pans to make 24 three inch doughnuts with baking spray.
With an electric mixer, beat together the butter and sugar until light and fluffy.
Add the eggs and vanilla, and beat until combined.
Add the chocolate, and mix to combine.
Sift together the flour, baking soda, and salt, into a small bowl.
Add half the flour to the sugar/eggs/chocolate and mix. Then add the buttermilk, and mix. And, then add the rest of the flour, and mix.
Add ⅔ cup of boiling water, and mix.
Using a measuring cup, fill up the doughnut tins. Bake ten minutes, or until the doughnuts bounce back when pressed. Cool for five minutes on a wire rack and then unmold and glaze. Then sprinkle with sprinkles.