Preheat the oven to 180°C/350°F and grease a 9-inch square pan with butter and line with parchment paper

In a mixing bowl cream together the butter and sugar until there are no traces of sugar

Add the eggs, one at a time, whisking until fully incorporated after each addition. With the last egg add the vanilla extract

Add half of the plain flour and the baking powder then mix until just combined

Add the remaining flour along with the milk then mix until there are no traces of flour

Pour the batter into the tin and bake in the oven for 25-30 minutes or until the skewer comes out clean

Allow the cake to cool completely before preparing the glaze

In a small bowl add the icing sugar and the water then mix until well combined – the icing should slowly glide off the spoon when lifted, if it is too thick then add a drop of water at a time until the right consistency is reached

Pour the glaze on top of the cake then top with the sprinkles

Allow to set for 10 minutes, then cut into slices before serving