Preheat oven at 180°C/350°F. Grease and flour a 24cm (10-inch) springform pan.
In a bowl, cream together butter and sugar until light and fluffy. Add the eggs, one at a time, and the vanilla.
Fold in the flour and baking powder and mix to combine. Pour the batter into the prepared pan and place the peach slices on top in a circular pattern. Sprinkle with white sugar and bake for 40-45 minutes, or until a toothpick inserted in the center comes out clean. Let it cool a little before turning onto a wire rack.
