To make the cupcakes
Preheat the oven to 180 degrees, and line a12 hole cupcake tin with paper cases
Put the butter, sugar, flour, milk, vanilla and eggs in a bowl and beat with electric beaters on a low speed for 2 minutes or until well mixed
Increase speed and beat for a further 2 minutes or until smooth and pale
Add the bag of Mini M&Ms and on the lowest speed, mix into the batter.
Spoon mixture in to cupcake tray and bake for 20 minutes or until golden and cooked through.
Allow to cool completely on a wire rack
To make the Vanilla Frosting
Cream butter and sugar together using an electric mixer until white and fluffy. Add vanilla extract and continue to beat until combined.
Put icing into a piping bag, fitted with a star shaped nozzle.
Pipe icing onto the top of the cupcakes in a circular motion, starting from the outside edge until cupcake is covered.
Sprinkle 100s & 1000s over the top to decorate.