• Preheat the oven to 180'C/Gas 4. Grease and line (with baking paper) a fixed-bottom, 20cm cake tin. (Note: A loose bottom or springform tin won't work as the caramel will just seep out. Trust me, I learnt the hard way!)
• Peel, quarter and core the apple. Cut each quarter into four wedges and then arrange the apple slices on the bottom of the baking tin.

First make the toffee sauce:

• Add the sugar, butter and golden syrup to a large pan and place on a low heat. Stir until the butter has melted and the sugar has dissolved.
• When it starts bubbling, add the double cream, stir and bring to the boil. Boil for 20-30 seconds, then remove from the heat completely and allow to cool slightly while you make the cake mixture.

Next make the cake batter:

• Add the butter and sugar to a large mixing bowl. Using an electric whisk, beat for 1-2 minutes until thoroughly mixed.
• Add the Greek yoghurt, eggs and milk and beat again until you have a loose, wet batter.
• In a separate bowl, mix the gluten free flour, xanthan gum, baking powder and ground almonds together. Pour into the cake batter and mix again with an electric whisk until you have a thick batter.
• Pour around three-quarters of the toffee sauce over the apples, making sure it is spread evenly. Reserve the remaining sauce for serving.
• Gently spoon the cake mixture over the apple slices. You want to make sure all the apple and toffee is covered - but try not to mix it up too much. I find the best way is spooning small 'dollops' into the tin until it is all covered, then smooth the top.
• Bake in the middle of the oven for approx 1 hour. Test the cake by seeing if a skewer in the centre comes out clean. If not cooked, put back in the oven for 10 minutes more.
• Remove and cool on a wire rack for at least 30-45 minutes before turning out. Serve warm with the extra toffee sauce warmed up and poured over the top of each slice!