Preheat oven to 180C/350F/Gas 4 and place 24 cupcake liners into cupcake pans.
To make the cupcakes use a stand or handheld mixer. Place the cake mix, eggs, ½ cup of butter, milk, and vanilla bean paste into a bowl and mix on medium speed until combined.
Divide the cupcake batter between 3 bowls.
Add red gel food coloring to one bowl and mix it to the desired shade.
Add sky blue gel food coloring to one bowl and mix it to the desired shade.
Leave the third bowl of batter as is.
Add 1 tablespoon of red batter to each cupcake liner, followed by 1 tablespoon of sky blue, and 1 tablespoon of white.
Repeat adding a tablespoon of each color again so the cupcake liners are about three-quarters full.
Bake for 20 minutes or until an inserted toothpick comes out clean.
Allow cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely before decorating.
To make the frosting use a stand or handheld mixer. Place the butter, powdered sugar, vanilla extract, and heavy whipping cream into a bowl and mix on medium speed until you get creamy stiff peaks.
If your frosting starts looking like powdery rocks, add another tablespoon of cream.
Scoop one-quarter cup of frosting into 3 bowls.
Add red gel food coloring to one bowl and mix it to the desired shade.
Add sky blue gel food coloring to another bowl and mix it to the desired shade.
Leave the third bowl of frosting white.
Fit a medium star tip to a large piping bag and place it inside a large cup, pulling the bag over the cup's edge.
Spoon the red icing down one-third side of the piping bag.
Spoon the blue icing down another one-third side of the piping bag.
Spoon the quarter cup of white icing down the final one-third side of the piping bag.
Twist the top of the piping bag and squeeze the frosting down to the tip. Set aside.
Use an ice cream scoop to add a scoopful of the remaining white icing onto each of the cupcakes.
Flatten the top and smooth out - remove any excess if you feel necessary.
Pour the sprinkles into a bowl and dip the frosted cupcake in the sprinkles to cover the top and sides.
Pipe a small swirl of the multi-colored frosting on top of the sprinkle-covered frosting.
Add a star topper to each cupcake and enjoy!