Ingredients
Method
1.Preheat oven to 180°C (160°C fan-forced). Grease and line base and side of a 24cm (base diameter) round spring form pan with baking paper. Place chilled butter and plain flour in a bowl; rub with fingertips to make coarse crumbs. Stir in sugar and half the cinnamon. Add apple; toss gently to combine. Set aside.
2.Using an electric mixer, beat extra butter and extra sugar in a bowl until pale and creamy. Add eggs, one by one, beating lightly after each addition. Beat in sour cream. Using a metal spoon, fold in sifted self-raising flour and remaining cinnamon until just combined.
3.Spoon mixture into prepared pan; level surface. Place apple mixture over surface of cake batter. Bake for 50 minutes or until a skewer inserted at centre comes out clean.
4.Stand in pan for 5 minutes. Transfer to a wire rack. Serve, warm or cool, with ice-cream.
Tip: Bake a day ahead. Store cooled cake in an airtight container at room temperature.
Note