INGREDIENTS
3/4 cup
all-purpose flour
3/4 cup
plus 1 tablespoon (170 g) superfine sugar (or regular granulated sugar, see Sweetapolita's Notes)
1/2 cup
extra dark OR dark Dutch-process cocoa powder
1 tsp
baking soda
1/2 tsp
baking powder
1/2 tsp
salt
1/2 cup
buttermilk, room temperature
1/3 cup
hot coffee OR boiling water
3 tbsp
vegetable oil
2 tsp
pure vanilla extract
1
egg, room temperature
1 cup
plus 2 tablespoons (255 g) unsalted butter, softened
1 cup
confectioners' sugar
1/3 cup
premium dark cocoa powder (I used Guittard Noir)
1/4 cup
hot water
1/4 cup
sour cream OR plain Greek Yogurt
1 tsp
pure vanilla extract (I used Nielsen-Massey)
Generous pinch of salt
5 oz
premium dark (but not extra dark) chocolate, chopped or chips, melted (I used Callebaut Callets)
Your favourite sprinkles (I used the Jersey Shore Sprinkle Medley from my shop)
You will also need:
1
large pastry bag, disposable or reusable
Large plain round pastry tip (I use Ateco #809)