In a large bowl beat together the butter and two sugars until creamy.
In another bowl/jug whisk together the milk, eggs and vanilla extract.
Add ⅓ of the wet ingredients into the butter mixture and mix on a slow/medium speed. Sift together the dry ingredients and mix in ½ of the dry ingredients.
Scrape down your bowl and beat in ½ the remaining wet ingredients followed by the rest of the dry ingredients. Once combined pour in the remaining wet ingredients.
Once the mixture is smooth, evenly divide it into the mini cupcake cases. You will need 35 red, 27 blue, 2 yellow, 43 peach and 31 brown. 138 in total.
Bake in a preheated oven at 190ºC for 10-11 minutes or until a skewer comes out clean. This will be longer if you are using larger cases.
Repeat until all cupcakes have been made. Leave to cool on a wire rack.
Sift the icing sugar into a bowl and beat it into the butter. Once sandy pour in the milk to combine.
Beat for a good 5 minutes until the icing is paler in colour and light and fluffy. Divide the buttercream into 4 bowls allowing more buttercream for the peach and red colours since there are more cupcakes with those colours. Colour each bowl of buttercream using a gel food colour,
Beat the butter and sifted icing sugar together until sandy. Add the milk and continue beating. Sift over the cocoa powder and beat until well mixed. Pour in the melted and cooled chocolate and beat for a good 5 minutes until light and fluffy.
Transfer all the coloured buttercream and chocolate buttercream into individual piping bags and cut a small hole at the end, no piping tip needed. Pipe a small dollop onto each cupcake making sure to cover as much cupcake as possible.
Arrange the cupcakes onto your chosen serving board following the pixel design. Enjoy :D