Preheat the oven to 180C/350F/Gas 4 and place paper cases in a 12 hole muffin tin
Combine the butter and sugar in a bowl until pale and fluffy.
Beat in the eggs a little at a time and then add the vanilla essence.
Fold in the flour using a large metal spoon, adding a little milk until the mixture is soft.
Transfer the mixture into the paper cases filling each case half way full. Allow to bake for 10-15 minutes until golden.
Leave to cool for 10 minutes on a wire rack.
For the buttercream icing, beat the butter in a bowl and then add half the icing sugar and beat until the mixture is smooth.
Add the rest of the icing sugar, 1 to2 drops of food colouring, and one tablespoon of the milk, more if necessary, until the icing is smooth and creamy.
To make the grass style icing: Firstly smear a little icing on each cupcake; this will stop the cupcake showing through.
In order to make the grass effect, you need an icing tip with several small holes in it (We used Wilton #233).
Fill the icing bag with icing and holding the bag straight down, squeeze the bag slightly and pipe all over the cupcake for grass effect.
Decorate with mini eggs or jelly beans and leave to set for a few hours.