Method

​1 Preheat the oven to 180°C/fan 160°C/gas mark 4. Grease a 9 inch (23 cm) round cake tin and line the base with baking parchment.

2 Put the butter/margarine, sugar, eggs, gluten-free flour and gluten-free baking powder into a large bowl. Using an electric whisk beat well for about 2 minutes until combined together. Next mix in the chopped walnuts and sultanas with a wooden spoon.

3 Spoon half the mixture into the prepared tin then spread the grated apple and ground cinnamon in an even layer on top. Spread the remaining cake mixture on top, making sure you level the surface.

4 Bake in the oven for about 1 hour 30 mins or until the cake is well risen and golden brown. Leave to cool in the tin for about 10 minutes then finish cooling on a wire rack.