This pretty cake is perfect for afternoon tea.
Preheat oven to 170ºC. Grease and line base and sides of a 20cm diameter spring form pan.
Using an electric mixer, beat butter, caster sugar and vanilla together in a medium bowl until pale and creamy. Beat in eggs, one at a time.
Stir in sifted flour alternately with milk. Stir until smooth. Spoon into prepared pan. Place apple slices on top of cake in a circular pattern. Brush with melted butter.
Bake for 40 minutes. Combine sugar and cinnamon. Sprinkle evenly over cake.
Cool cake for 10 minutes before removing sides of pan. Place on a wire rack to cool completely.