Watercolor Buttercream Party Cake

INGREDIENTS

2 1/4 cups

all-purpose flour

2 1/4 cups

superfine sugar

1 cup

dark unsweetened cocoa powder (see Notes)

1 tbsp

baking soda

1 1/2 tsp

baking powder

1 tsp

salt

1 1/2 cups

buttermilk, room temperature

1 cup

hot coffee (if you can't use coffee, substitute with very hot water)

3/4 cup

vegetable oil

2 tsp

pure vanilla extract

eggs, room temperature

1 cup

unsalted butter, softened

1/2 cup

vegetable shortening (see Notes)

salt

5 cups

confectioners' sugar

2/3 cup

heavy cream

1 tbsp

warm water

2 tsp

vanilla bean paste (see Notes)

Bright pink food colouring (see Notes)

Edible gold leaf, optional (see Notes)

Pink sprinkles, optional