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.