Preheat oven to 160°C (fan forced). Grease a 20cm (base measurement) round cake tin and line the base and sides with baking paper.
In a large bowl add butter, vanilla and sugar and beat on high speed using an electric mixer or food processor until light and fluffy. Gradually pour in eggs, continuing to beat after each addition.
Finally, gently fold in flour, baking powder and milk until well combined.
Pour mixture into prepared cake tin and smooth the surface with the back of a spoon. Bake for for 45 minutes or until a skewer inserted into the middle comes out clean.
Allow cake to stand in tin for 5 minutes before turning out onto a wire rack to cool completely.