Vanilla Cupcakes with Swirled Rainbow Frosting

Vanilla Cupcakes with Swirled Rainbow Frosting

  • Author: Jessica Holmes
  • Prep Time: 40 minutes
  • Cook Time: 20 minutes
  • Total Time: 1 hour
  • Yield: Makes 12 cupcakes
  • Category: Dessert
  • Cuisine: American


Light and fluffy Vanilla Cupcakes with Swirled Rainbow Frosting with a tender crumb, thanks to a little sour cream – and a dollop of vanilla buittercream.


Vanilla cupcakes

  • 115 grams (1/2 cup or 1 stick) unsalted butter, room temperature
  • 150 grams (3/4 cup) caster sugar
  • 2 teaspoons vanilla extract
  • 1 large egg, room temperature
  • 175 grams (1 and 1/4 cup) plain flour
  • 1 and 1/2 teaspoons baking powder
  • 120 ml (1/2 cup) milk, room temperature
  • 60 ml (1/4 cup) sour cream, room temperature

Rainbow frosting

  • 1/2 cup (115 grams or 1 stick) unsalted butter, softened
  • 4 cups (500 grams) icing or powdered sugar
  • 23 tablespoons milk
  • Three different coloured food gels – I used purple, teal and violet.


  1. Preheat the oven to 160 C (320 F). Line a 12-hole muffin pan with cupcake liners. In a large mixing bowl, beat the butter and sugar together until pale and creamy. Add the vanilla and beat again. Add the egg, beat again, then scrap down the sides. In a separate bowl, sift the plain flour and baking powder together.
  2. Add half of the flour mixture to the butter and half of the milk and slow mix together on a low speed. Add the rest of the flour and the milk and continue to mix until combined. Finally, add the sour cream and mix until smooth and creamy. Pour the cake batter into your prepared tin and bake in the oven for approximately 18-20 minutes Leave to cool completely on a wire rack.
  3. To make the icing, add the butter to a large mixing bowl, beat with an electric mixture until soft and creamy. ¬†Gently sift in one cup of the icing sugar and continue to beat. Add a tablespoon or two of milk to help loosen up the mixture. Add the rest of the icing sugar, one cup at a time. Continue to add a tablespoon of milk as needed – but be careful, you don’t want the frosting too runny. It should be nice and creamy but thick enough to hold its shape when piped. Divide the icing into three bowls.
  4. In each bowl, add a few drops of food colouring and stir thoroughly until the icing is dyed to the colours you want. Grab your disposable piping bag and insert a large star tip into the end. Very gently add spoonfuls of one colour of icing and try keep it to one side of the piping bag. You don’t have to be exact, so do the best you can. Then gently spoon the second coloured icing on top and then the third colour on top of that. Gently press down to remove any air bubbles and force the icing down to the tip. Twist the top of the bag and then pipe the icing onto the cupcakes.


The first time you use pipe the frosting, ¬†it probably won’t have all three colours so use that one as a test run.

Keywords: Cupcakes, Vanilla, Frosting

Recipe Card powered by