Preheat your oven to 180C / 160 fan / gas 4 and add 10 cupcake cases into a cupcake tray.
Beat the butter and the sugar together, using an electric whisk or hand whisk, do this until fluffy.
Whisk the eggs together, then add them gradually into the mixture. Followed by your vanilla extract.
Following on from this sift your flour into your mixture, bit by bit. The sifting part allows air into the flour and provides a lighter and fluffier cake.
Once all of your ingredients have been added, separate them into 4 different bowls. One for each colour.
Put a heaped tbsp of each colour into your cases until you’re out of colours.
Cook for 22-25 minutes, take out the oven and pop a cocktail stick through your cupcake. If it comes out clean then your cakes are ready. If not pop them back in. Once ready, allow your cakes to cool for 10-15 minutes before using buttercream.
To make your buttercream, you need to mix your icing sugar and butter together. Make sure to this slowly to avoid it becoming grainy.
Once fluffy, add your vanilla extract and milk and then stir in.
Top the cupcakes by pipping on the buttercream, alternatively spoon on to the top.
Finally add your rainbow drops to the top. I’d recommend crushing some up for a dusting as well as adding plenty of whole ones.
Once you've done this, your cakes are ready to be enjoyed! Share these with friends and family for a throwback treat.