Cook the sugar in a medium saucepan over a moderate heat for 10 minutes, until deep caramel.
Pour in 50ml (3 Tbsp) cream and 50g (3 Tbsp) butter and stir until smooth. Pour half the caramel into the bottom of a lined 21cm square cake tin.
Return the remaining sauce to the stove and cook over a low heat. Add the remaining cream and 75g (¼ cup) butter, whisking until smooth. Set aside.
Slice the JAZZ™ apples ½cm thick and remove any seeds. Arrange in the caramel sauce in the base of the cake tin.
Combine the flours, spice, sugar, buttermilk, eggs, vanilla and remaining butter in the bowl of an electric mixer and beat until a smooth batter forms. Pour over the JAZZ™ apples.
Bake for 45 minutes, until a skewer can be inserted and removed cleanly. Serve warm with the reserved butterscotch sauce and vanilla ice cream.