Apple crumble cake

Ingredients

For the topping: 1/4 cup self-raising flour, 1/2 teaspoon cinnamon, 3 tablespoons butter, 2 tablespoons caster sugar. For the base: 4 tablespoons butter softened, 6 tablespoons caster sugar, 1 size 3 egg beaten, 1 cup self-raising flour sifted, 2 cooking apples peeled cored and sliced, 1/3 cup sultanas. To decorate: 1 red dessert apple cored thinly sliced and tossed in lemon juice, 2 tablespoons caster sugar sifted, pinch of ground cinnamon