INGREDIENTS
2 1/3 cups
all-purpose flour
3/4 cup
plus one tablespoon (100 g) best-quality black cocoa powder
1
1 /2 teaspoons baking powder
3/4 tsp
salt
1 1/2 cups
buttermilk, room temperature
1/2 cup
hot coffee OR very hot water
1 cup
unsalted butter, room temperature
2 1/2 cups
packed light brown sugar
2 tsp
pure vanilla extract
4
large eggs, room temperature
1/4 cup
mayonnaise, room temperature
1 1/2 tsp
baking soda
1 tsp
distilled white vinegar
1 cup
unsalted butter, room temperature
3 cups
confectioners' sugar, sifted
1/4 cup
whipping cream (heavy cream) or milk
2 tbsp
water (plus more if needed)
2 tsp
pure vanilla extract
salt
Few drops each AmeriColor Soft Gel Paste Color in Electric Purple and Regal Purple
2 cups
unsalted butter, softened
4 cups
confectioners' sugar
3/4 cup
premium dark (preferably black) cocoa powder (I used Guittard Noir)
1/2 cup
hot water
1/2 cup
sour cream
1 1/2 tsp
pure vanilla extract (I used Nielsen-Massey)
Generous pinch of salt
8 oz
premium dark (but not extra dark) chocolate, chopped or chips, melted (I used Callebaut Callets)
Soft gel paste color, in Super Black (or other concentrated black gel color of your choice, but this one is the only I can promise works for black coloring)
Sprinkles of your choice (1-2 cups, depending on size of the sprinkles)
You will also need:
1
large pastry bag, disposable or reusable
Large plain round pastry tip (I use Ateco #809)
Sprinkles of your choice (1-2 cups, depending on size of the sprinkles--see Sweetapolita's Notes)