Easy Rainbow Cookies (Fun, Colourful & So Simple)

These rainbow cookies are one of those bakes that instantly make people smile. Perfect for parties, pride or St Patrick’s Day celebrations.

These cookies are bright, playful, and honestly so easy to make! We’re using a simple chocolate chip cookie and turning it into something a little bit special with colourful icing.

Why You’ll Love These Rainbow Cookies

• Made using a simple, everyday cookie recipe
• No need for complicated baking skills
• Perfect for birthdays, parties, or rainy day baking
• Easy to customise with different colours
• Try our Rainbow Fruit Platter (Fun, Healthy & Perfect for Parties) too!

Ingredients

For the 5 large cookies:

• 100g unsalted butter, softened to room temperature
• 100g light brown sugar
• 30g caster sugar (white sugar)
• 1 large egg
• 100 g plain flour
• 100 g self-raising flour
• ½ tsp baking powder
• 1 pinch salt (optional, but recommended)
• 200 g milk or dark chocolate, chopped into chunks (feel free to leave the chocolate out for a plain cookie)

For the decoration:

• Red food colouring
• Yellow food colouring
• Blue food colouring
• 250g unsalted butter
• 500g icing sugar
• 1 tsp vanilla extract

How to Make Rainbow Cookies

1. Preheat your oven to 180°C (fan). Line a baking sheet with parchment paper.
2. In a large bowl (or the bowl of a stand mixer or electric mixer), beat the softened butter with the light brown sugar and caster sugar until combined. Scrape down the bottom of the bowl so everything mixes evenly.
3. Mix in the egg and beat until smooth.
4. In a separate bowl, combine the plain flour, self-raising flour, baking powder, and salt.
5. Add the dry ingredients to the wet ingredients and mix just until combined. 
6. If you are using chocolate chunks, gently fold through the chocolate so they’re evenly distributed throughout the dough.
7. Use a cookie scoop or ice cream scoop for evenly sized cookies I use 2 standard size ice cream scoops for each cookie.
8. Place dough balls onto the prepared baking sheet, leaving space for spreading
9. Bake for 10–12 minutes, depending on your oven temperature. I usually bake for 10 minutes and add 1-2 minutes if my dough is frozen

How to decorate the cookies

You can buy pre-made colours, but this is a simple way to create a full rainbow using just red, blue, and yellow food colouring.

1. Prepare your favourite buttercream by adding the softened unsalted butter to a bowl and use the stand mixer. Gradually combine the icing sugar, a splash of milk, and vanilla extract) until smooth and fluffy
2. Split the buttercream evenly into 7 small bowls, one for each colour of the rainbow including the white for the clouds.
3. To create your colours start with the three primary colours, red, blue and yellow
4. To make orange mix red and yellow
5. For green mix blue and yellow
6. To make purple combine red and blue
7. Adjust shades gradually and add the food colouring a tiny drop at a time and mix well. This helps you control the tone and avoid overly strong colours.
8. To create lighter tones, like softer, pastel shades, mix in a little extra plain buttercream.
9. Use immediately, or cover each bowl with plastic wrap to prevent drying.
10. Transfer each colour into 7 small piping bags and snip a small end off each bag
11. Cut each cookie into halves and pipe the colours separately onto the cookie in a rainbow shape. Pipe the clouds last over the top of the rainbow at the bottom.

Tips for Best Results

• Gel food colouring works best for vibrant colours without thinning the icing
• Always start light as you can add more colour, but you can’t take it away
• Mix thoroughly to avoid streaks
• If the buttercream softens too much, chill briefly before using

Storage

• Store in an airtight container for up to 4 days

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