01 -
Preheat your oven to 320°F (160°C) fan-forced or 356°F (180°C) conventional. Line cupcake tins with 20 cupcake liners.
02 -
In a large mixing bowl, combine the flour, sugar, cocoa powder (if using), baking powder, baking soda, and salt. Mix on low speed until well combined, or sift together if mixing by hand.
03 -
In a large jug, whisk together the eggs, vegetable oil, buttermilk, vanilla extract, and blue food coloring (if using) until well combined.
04 -
Slowly pour the wet ingredients into the dry ingredients while mixing on low speed. Once all wet ingredients are incorporated, stop the mixer, scrape down the sides of the bowl, and mix for another 20 seconds until smooth.
05 -
Fill each cupcake liner about halfway with batter. Bake for 30 minutes until the tops look slightly shiny and bounce back when lightly touched. Cool completely on a wire rack before decorating.
06 -
Once cooled, use a cupcake corer or small knife to remove the center of each cupcake. Fill the holes with star sprinkles for a surprise inside.
07 -
Divide your prepared buttercream frosting into three separate bowls. Color one purple (using pink and purple gel), one blue, and one pink according to the color combinations in the ingredients list. Mix each thoroughly with a spatula.
08 -
Fit a piping bag with a Wilton 6B tip and place it in a tall cup. Add 1 teaspoon of each colored frosting, alternating colors, until the bag is just over half full.
09 -
Place each colored frosting in separate piping bags. Lay out a large piece of plastic wrap and pipe lines of each color side by side, leaving about an inch gap at the top and bottom. Roll the plastic wrap into a log, twist the ends, and snip off one end. Place this into a piping bag fitted with a Wilton 6B tip.
10 -
Pipe a swirl of frosting on top of each cupcake, starting from the outside and working toward the center. Immediately sprinkle with edible glitter and silver star sprinkles before the frosting sets.