• In a double boiler, melt butter and baker's chocolate. Remove from heat.
• In a large bowl, whisk flour, sugar, cocoa, baking powder, baking soda, and salt.
• Add buttermilk and vanilla to melted chocolate. Add whisked egg.
• Add wet ingredients to dry and mix until combined. With your hands, mix until dough is all well combined and form into a ball. Wrap in plastic and cool in fridge for 30 minutes.
• Once cooled, roll dough into 1 -2 tablespoon balls.
• Heat a deep skillet or sauce pan with 3 inches of vegetable oil until oil reaches 350 degrees (candy thermometers or digital infrared thermometer). Add 4 - 5 balls into the oil and fry until cooked (they'll looked a little puffed), approximately 2-4 minutes. With a slotted spoon, remove from oil and place on paper towel lined plate. Finish with all balls.
• Line baking sheet with parchment paper and rack.

Prepare the Glaze

• In a medium sized bowl, whisk confectioner's sugar, milk and vanilla until the consistency of heavy cream. If needed, add a little water and mix to reach that consistency.
• Dip each donut hole in the glaze. With a fork, remove and shake off excess glaze. Transfer donuts to rack until all donut holes are glazed. Let rest until glaze is set.
• Enjoy!
• Store in an airtight container for up to a week.