Preheat the oven to 180ºc/160ºfan, and line a muffin tray with 12 cases - or get 12 baking cups ready.
In a large bowl, add the unsalted butter and caster sugar and beat together until light and fluffy.
Add the self raising flour, eggs, and vanilla extract and beat again until smooth and perfect.
Split the mixture between the 12 cases and bake the cupcakes in the oven for 20-22 minutes, or until baked through.
Leave the cupcakes to cool fully.
Decoration
Once the cupcakes have cooled fully, beat the butter on its own in a large bowl until smooth. I do this for a few minutes.
Add the icing sugar and vanilla extract and beat again until a buttercream is formed.
Split the buttercream into three equal portions
Add the blue food colouring to one third of buttercream and beat on it's own until the buttercream is lovely blue colour.
Repeat this with the red food colouring on another third of the buttercream
Leave the third as it is (white).
Lay a large piece of clingfilm onto your work surface and line the three colours of buttercream up in the middle, and then roll the clingfilm up into a sausage shape.
Once this is done, snip off the end and add the clingfilm to a piping bag with a piping tip.
Pipe the buttercream onto the cupcakes, sprinkle on any sprinkles you fancy and enjoy!
Notes
These cupcakes are the perfect bake for the jubilee, but you can of course make them any time of year, and change the colours to what you fancy!